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Sanches-Neto F, Coutinho N, Aquilanti V, Silva W, Carvalho-Silva V. Mechanism and Kinetics of The Degradation of Nitazoxanide and Hydroxychloroquine Drugs by Hydroxyl Radicals: Theoretical Approach to Ecotoxicity. J BRAZIL CHEM SOC 2023. [DOI: 10.21577/0103-5053.20230025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
Abstract
The efforts of contrasting the effects caused by the Covid-19 (coronavirus disease 2019) pandemic increased the disposal of active pharmaceutical ingredients. This paper reports the mechanisms and kinetics of the degradation in aqueous environments induced by OH of two drugs, among those most widely probed at the outbreak of coronavirus, nitazoxanide and hydroxychloroquine. The investigation exploits quantum chemistry techniques and a reaction rate theory combined with diffusion-controlled processes and quantum mechanical tunneling. The reaction rate constants are obtained in an environmentally relevant temperature range. The results show that (i) the deacetylation of nitazoxanide with formation of tizoxanide is kinetically the most favorable channel, in agreement with experimental work; (ii) for hydroxychloroquine, the present theoretical calculations show that the most favorable channel is the addition of OH at the aromatic ring. The half-life time degradation products are for both cases in the range between 12 to 138 days. Both drugs presented toxicities between harmful and toxic as obtained by computational toxicology calculations: The toxicity is also calculated for the degradation products: (i) in the nitazoxanide degradation process, tizoxanide was characterized as more toxic, while (ii) in the case of hydroxychloroquine, the major degradation product showed a decrease in the toxicity.
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Correa E, Albernaz AF, Barreto PR, Aquilanti V. Long-range strength and anisotropies of molecule-molecule interactions: Ab initio calculations, spherical harmonics expansions, and the second virial coefficient for the H2⋯F2 gaseous mixture. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Che DC, Nakamura M, Chang HP, Lin KC, Kasai T, Aquilanti V, Palazzetti F. UV Photodissociation of Halothane in a Focused Molecular Beam: Space-Speed Slice Imaging of Competitive Bond Breaking into Spin-Orbit-Selected Chlorine and Bromine Atoms. J Phys Chem A 2020; 124:5288-5296. [PMID: 32498517 DOI: 10.1021/acs.jpca.0c02800] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A molecular beam of halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) is focused by a hexapolar electrostatic field and photolyzed by UV laser radiation at 234 nm. Angular and speed distributions of chlorine and bromine photofragments emitted from halothane are measured for both spin-orbit states independently. Although the dissociation energy of the C-Cl bond is larger than that of C-Br, the relative yield of Cl to Br was found to be approximately 2. Measured speed and angular distributions of atomic fragments show distinct kinetic energy release and scattering characteristics: for bromine, observed fast and aligned fragments exhibit a signature of a direct mode of dissociation for the C-Br bond, via the electronically excited potential energy surface denoted nσ*(C-Br), of repulsive nature; for chlorine, a variation in the features is observed for the dissociation pathway through nσ*(C-Cl), from a modality similar to the bromine case, leading to fragments with appreciable kinetic energy release and pronounced directionality, to a modality involving slow products, nearly isotopically distributed. The origin of this behavior can be attributed to nonadiabatic interaction operating between the nσ*(C-Br) and nσ*(C-Cl) surfaces. These results are not only relevant for a detailed understanding of adiabatic versus diabatic coupling mechanisms in the manifold of excited states populated by photon absorption, but they also point out the possibility of selectively inducing specific dissociation pathways, even when involving energetically unfavorable outcomes, such as, in this case, the prevailing rupture of the stronger C-Cl bond against that of the weaker C-Br bond.
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Affiliation(s)
- Dock-Chil Che
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Hsiu-Pu Chang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.,Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.,Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia 06123, Italy.,Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Rome 00016, Italy
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia 06123, Italy
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De Fazio D, Aquilanti V, Cavalli S. Benchmark Quantum Kinetics at Low Temperatures toward Absolute Zero and Role of Entrance Channel Wells on Tunneling, Virtual States, and Resonances: The F + HD Reaction. J Phys Chem A 2020; 124:12-20. [PMID: 31829589 DOI: 10.1021/acs.jpca.9b08435] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper reports a study of the quantum reaction dynamics and kinetics of the F + HD reaction at low and ultralow temperatures, focusing on the range from the Wigner limit up to 50 K. Close coupling time-independent quantum reactive scattering calculations for the production of HF and DF molecules have been carried out on two potential energy surfaces differing in the description of the reaction entrance channel. This case is computationally more demanding than the cases of F with H2 and D2 ( De Fazio et al. Frontiers in Chemistry 2019 , 7 , 328 ) but offers a wider phenomenology regarding the roles of quantum mechanical effects of tunneling, of virtual states, and of resonances. The results show that at the temperatures in the cold and ultracold regimes small changes in the entrance channel long-range interaction induce surprising near threshold features. The presence of a virtual state close to the reactive threshold gives rise to a marked anti-Arrhenius behavior of the rate constants below 100 mK. This effect enhances reaction rates by about 2 orders of magnitude, making them of the same order as those at room temperature and confining the onset of the Wigner regime in the microkelvin region.
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Affiliation(s)
- Dario De Fazio
- Istituto di Struttura della materia-Consiglio Nazionale delle Ricerche , 00016 Roma , Italy
| | - Vincenzo Aquilanti
- Istituto di Struttura della materia-Consiglio Nazionale delle Ricerche , 00016 Roma , Italy.,Dipartimento di Chimica, Biologia e Biotecnologie , Università di Perugia , 06123 Perugia , Italy
| | - Simonetta Cavalli
- Dipartimento di Chimica, Biologia e Biotecnologie , Università di Perugia , 06123 Perugia , Italy
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Nakamura M, Chang HP, Lin KC, Kasai T, Che DC, Palazzetti F, Aquilanti V. Stereodynamic Imaging of Bromine Atomic Photofragments Eliminated from 1-Bromo-2-methylbutane Oriented via Hexapole State Selector. J Phys Chem A 2019; 123:6635-6644. [PMID: 31177785 DOI: 10.1021/acs.jpca.9b04048] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Both single-laser and two-laser experiments were conducted to look into the ion-imaging of Br*(2P1/2) and Br(2P3/2) photofragmented from 1-bromo-2-methylbutane in the range 232-240 nm via a detection scheme of (2+1) resonance-enhanced multiphoton ionization. The angular analysis of these photofragment distributions yields the anisotropy parameter β = 1.88 ± 0.06 for the Br* excited state which arises from a parallel transition, while β = 0.63 ± 0.09 for the Br ground state indicates the contribution from both a perpendicular transition and a non-adiabatic transition. When a hexapole coupled with an orienting field was implemented, the parent molecules are spatially oriented to yield an orientation efficiency |⟨cos θ⟩| of 0.15. Besides the χ angle between the recoil velocity v and the transition dipole moment μ, orienting molecules allows for the evaluation of the angle α between v and the permanent molecular dipole moment d. The angular analysis of Br* photofragment distribution yields χ = 11.5° and α in the range from 160° to 180° with weak dependency. In the two-laser experiments, the angular anisotropy of Br photofragment distribution was found to be smaller (0.38 ± 0.10) when the photolysis wavelength was red-shifted to 240 nm, suggesting the increasing contributions from perpendicular transitions.
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Affiliation(s)
- Masaaki Nakamura
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
| | - Hsiu-Pu Chang
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan
| | - King-Chuen Lin
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan.,Institute of Atomic and Molecular Sciences , Academia Sinica , Taipei 10617 , Taiwan
| | - Toshio Kasai
- Department of Chemistry , National Taiwan University , Taipei 10617 , Taiwan.,Institute of Scientific and Industrial Research , Osaka University , Ibaraki, Osaka 567-0047 , Japan
| | - Dock-Chil Che
- Department of Chemistry, Graduate School of Science , Osaka University , Toyonaka, Osaka 560-0043 , Japan
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie , Università di Perugia , 06123 Perugia , Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie , Università di Perugia , 06123 Perugia , Italy.,Istituto di Struttura della Materia , Consiglio Nazionale delle Ricerche , 00016 Rome , Italy
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Nakamura M, Palazzetti F, Tsai PY, Yang SJ, Lin KC, Kasai T, Che DC, Lombardi A, Aquilanti V. Vectorial imaging of the photodissociation of 2-bromobutane oriented via hexapolar state selection. Phys Chem Chem Phys 2019; 21:14164-14172. [PMID: 30350830 DOI: 10.1039/c8cp04270e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular orientation techniques are becoming available in the study of elementary chemical processes, in order to highlight those structural and dynamical properties that would be concealed by random rotational motions. Recently successful orientation was achieved for asymmetric-top and chiral molecules of much larger complexity than hitherto. In this work, we report and discuss the correlation between the vectors' photofragment recoil velocity v, transition dipole moment μ, and permanent dipole moment d in a dissociation experiment on hexapole oriented 2-bromobutane, photoinitiated by a linearly polarized laser. The sliced ion images of the Br*(2P1/2) and Br(2P3/2) photofragments were acquired at 234.0 and 254.1 nm, respectively, by a (2 + 1) resonance-enhanced multiphoton ionization technique. A detailed analysis of the sliced ion images obtained at a tilting angle 45° of laser polarization provides information on the correlation of the three vectors, which are confined by two polar angles α and χ and one azimuthal angle φμd in the recoil frame. The sliced ion images of Br fragments eliminated individually from the enantiomers at 254.1 nm yield an asymmetric factor close to zero; for this reason the photofragment angular distributions do not show significant differences. The elimination of the Br* fragment at 234.0 nm is mainly correlated with a parallel transition, giving rise to a large anisotropy parameter of 1.85, and thus can be considered as a single state excitation. The resulting recoil frame angles are optimized to 163° ± 8° and 164° ± 1° for α and χ, respectively, whereas φμd is approaching 0° for the best fit. Since for the present molecule, the three vectors have an only slight spatial arrangement, the photofragment angular distributions of the two enantiomers do not show appreciable differences. Theoretical and computational simulations provide us the basis to state that oriented enantiomers can be discriminated on-the-fly in photodissociation processes even initiated by non-circularly polarized light, provided that the three vectors encountered above have specific three-dimensional arrangements. The fact that Br fragment elimination involves a multi-potential dissociation carries uncertainties in theoretical estimates of the vector direction. Therefore, this work represents a preliminary but significant step on the road to chiral discrimination on-the-fly, which is shown to be best propitiated in molecules where vectors are far from having degenerate mutual angular directions.
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Affiliation(s)
- Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.
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De Fazio D, Aquilanti V, Cavalli S. Quantum Dynamics and Kinetics of the F + H 2 and F + D 2 Reactions at Low and Ultra-Low Temperatures. Front Chem 2019; 7:328. [PMID: 31157204 PMCID: PMC6527900 DOI: 10.3389/fchem.2019.00328] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/24/2019] [Indexed: 11/29/2022] Open
Abstract
Integral cross sections and rate constants for the prototypical chemical reactions of the fluorine atom with molecular hydrogen and deuterium have been calculated over a wide interval of collision energy and temperature ranging from the sub-thermal (50 K) down to the ultra-cold regimes (0.5 mK). Rigorous close coupling time-independent quantum reactive scattering calculations have been carried out on two potential energy surfaces, differing only at long-range in the reactants' channel. The results show that tunnel, resonance and virtual state effects enhance under-barrier reactivity giving rise to pronounced deviations from the Arrhenius law as temperature is lowered. Within the ultra-cold domain (below 1 mK), the reactivity is governed by virtual state effects and by tunneling through the reaction barrier; in the cold regime (1 mK–1 K), the shape resonances in the entrance channel of the potential energy surface make the quantum tunneling contribution larger so enhancing cross sections and rate constants by about one order of magnitude; at higher temperatures (above 10 K), the tunneling pathway enhanced by the constructive interference between two Feshbach resonances trapped in the reaction exit channel competes with the thermally activated mechanism, as the energy gets closer to the reaction barrier height. The results show that at low temperatures cross sections and rate constants are extremely sensitive to small changes in the long-range intermolecular interaction in the entrance channel of the potential energy surface, as well as to isotopic substitution.
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Affiliation(s)
- Dario De Fazio
- Istituto di Struttura della Materia, Consiglio Nazionale Delle Ricerche (CNR), Rome, Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia, Italy
| | - Simonetta Cavalli
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia, Italy
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Carvalho-Silva VH, Coutinho ND, Aquilanti V. Temperature Dependence of Rate Processes Beyond Arrhenius and Eyring: Activation and Transitivity. Front Chem 2019; 7:380. [PMID: 31192196 PMCID: PMC6548831 DOI: 10.3389/fchem.2019.00380] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 05/10/2019] [Indexed: 12/02/2022] Open
Abstract
Advances in the understanding of the dependence of reaction rates from temperature, as motivated from progress in experiments and theoretical tools (e. g., molecular dynamics), are needed for the modeling of extreme environmental conditions (e.g., in astrochemistry and in the chemistry of plasmas). While investigating statistical mechanics perspectives (Aquilanti et al., 2017b, 2018), the concept of transitivity was introduced as a measure for the propensity for a reaction to occur. The Transitivity plot is here defined as the reciprocal of the apparent activation energy vs. reciprocal absolute temperature. Since the transitivity function regulates transit in physicochemical transformations, not necessarily involving reference to transition-state hypothesis of Eyring, an extended version is here proposed to cope with general types of transformations. The transitivity plot permits a representation where deviations from Arrhenius behavior are given a geometrical meaning and make explicit a positive or negative linear dependence of transitivity for sub- and super-Arrhenius cases, respectively. To first-order in reciprocal temperature, the transitivity function models deviations from linearity in Arrhenius plots as originally proposed by Aquilanti and Mundim: when deviations are increasingly larger, other phenomenological formulas, such as Vogel-Fulcher-Tammann, Nakamura-Takayanagi-Sato, and Aquilanti-Sanches-Coutinho-Carvalho are here rediscussed from the transitivity concept perspective and with in a general context. Emphasized is the interest of introducing into this context modifications to a very successful tool of theoretical kinetics, Eyring's Transition-State Theory: considering the behavior of the transitivity function at low temperatures, in order to describe deviation from Arrhenius behavior under the quantum tunneling regime, a "d-TST" formulation was previously introduced (Carvalho-Silva et al., 2017). In this paper, a special attention is dedicated to a derivation of the temperature dependence of viscosity, making explicit reference to feature of the transitivity function, which in this case generally exhibits a super-Arrhenius behavior. This is of relevance also for advantages of using the transitivity function for diffusion-controlled phenomena.
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Affiliation(s)
- Valter H. Carvalho-Silva
- Grupo de Química Teórica e Estrutural de Anápolis, Campus de Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, Anápolis, Brazil
| | - Nayara D. Coutinho
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Rome, Italy
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Aquilanti V, Capitelli M, Pegoraro F. Introduction: Classical and quantum plasmas—matter under extreme conditions. Rend Fis Acc Lincei 2019. [DOI: 10.1007/s12210-019-00786-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Coletti C, Aquilanti V, Palazzetti F. Hypergeometric orthogonal polynomials as expansion basis sets for atomic and molecular orbitals: The Jacobi ladder. State of The Art of Molecular Electronic Structure Computations: Correlation Methods, Basis Sets and More 2019. [DOI: 10.1016/bs.aiq.2019.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Coutinho ND, Sanches-Neto FO, Carvalho-Silva VH, de Oliveira HCB, Ribeiro LA, Aquilanti V. Kinetics of the OH+HCl→H 2 O+Cl reaction: Rate determining roles of stereodynamics and roaming and of quantum tunneling. J Comput Chem 2018; 39:2508-2516. [PMID: 30365178 DOI: 10.1002/jcc.25597] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/15/2018] [Accepted: 08/20/2018] [Indexed: 02/03/2023]
Abstract
The OH + HCl → H2 O + Cl reaction is one of the most studied four-body systems, extensively investigated by both experimental and theoretical approaches. Here, as a continuation of our previous work on the OH + HBr and OH + HI reactions, which manifest an anti-Arrhenius behavior that was explained by stereodynamic and roaming effects, we extend the strategy to understand the transition to the sub-Arrhenius behavior occurring for the HCl case. As previously, we perform first-principles on-the-fly Born-Oppenheimer molecular dynamics calculations, thermalized at four temperatures (50, 200, 350, and 500 K), but this time we also apply a high-level transition-state-theory, modified to account for tunneling conditions. We find that the theoretical rate constants calculated with Bell tunneling corrections are in good agreement with extensive experimental data available for this reaction in the ample temperature range: (i) simulations show that the roles of molecular orientation in promoting this reaction and of roaming in finding the favorable path are minor than in the HBr and HI cases, and (ii) dominating is the effect of quantum mechanical penetration through the energy barrier along the reaction path on the potential energy surface. The discussion of these results provides clarification of the origin on different non-Arrhenius mechanisms observed along this series of reactions. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Nayara D Coutinho
- Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970, Brasília, Brazil
| | - Flavio O Sanches-Neto
- Grupo de Química Teórica e Estrutural de Anápolis, Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, CP 459, 75001-970, Anápolis, GO, Brazil
| | | | - Heibbe C B de Oliveira
- Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970, Brasília, Brazil
| | - Luiz A Ribeiro
- Institute of Physics, University of Brasilia, Brasilia, 70910-900, Brazil
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy.,Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Area dela Ricerca di Roma Tor Vergata, Via del Fosso del Cavaliere, 00133, Rome, Italy
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Lin KC, Tsai PY, Chao MH, Nakamura M, Kasai T, Lombardi A, Palazzetti F, Aquilanti V. Roaming signature in photodissociation of carbonyl compounds. INT REV PHYS CHEM 2018. [DOI: 10.1080/0144235x.2018.1488951] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan (ROC)
| | - Po-Yu Tsai
- Department of Chemistry, National Chung-Hsing University, Taichung, Taiwan (ROC)
| | - Meng-Hsuan Chao
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
| | - Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
- Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Andrea Lombardi
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Consortium for Computational Molecular and Materials Sciences (CMS)2, Perugia, Italy
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Scuola Normale Superiore di Pisa, Pisa, Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Rome, Italy
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Falcinelli S, Vecchiocattivi F, Alagia M, Schio L, Richter R, Stranges S, Catone D, Arruda MS, Mendes LAV, Palazzetti F, Aquilanti V, Pirani F. Double photoionization of propylene oxide: A coincidence study of the ejection of a pair of valence-shell electrons. J Chem Phys 2018; 148:114302. [PMID: 29566526 DOI: 10.1063/1.5024408] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Propylene oxide, a favorite target of experimental and theoretical studies of circular dichroism, was recently discovered in interstellar space, further amplifying the attention to its role in the current debate on protobiological homochirality. In the present work, a photoelectron-photoion-photoion coincidence technique, using an ion-imaging detector and tunable synchrotron radiation in the 18.0-37.0 eV energy range, permits us (i) to observe six double ionization fragmentation channels, their relative yields being accounted for about two-thirds by the couple (C2H4+, CH2O+) and one-fifth by (C2H3+, CH3O+); (ii) to measure thresholds for their openings as a function of photon energy; and (iii) to unravel a pronounced bimodality for a kinetic-energy-released distribution, fingerprint of competitive non-adiabatic mechanisms.
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Affiliation(s)
- Stefano Falcinelli
- Dipartimento di Ingegneria Civile ed Ambientale, Università di Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Franco Vecchiocattivi
- Dipartimento di Ingegneria Civile ed Ambientale, Università di Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Michele Alagia
- IOM-CNR Tasc, Km 163.5, Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Luca Schio
- IOM-CNR Tasc, Km 163.5, Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Robert Richter
- Elettra-Sincrotrone Trieste, Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Stefano Stranges
- IOM-CNR Tasc, Km 163.5, Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Daniele Catone
- Istituto di Struttura della Materia (CNR-ISM), Area della Ricerca di Roma Tor Vergata, Via del Fosso del Cavaliere, 100-00133 Roma, Italy
| | - Manuela S Arruda
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Luiz A V Mendes
- Instituto de Fìsica, Universidade Federal da Bahia, Campus Universitario de Ondina, 40210-340 Salvador, BA, Brazil
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Vincenzo Aquilanti
- Istituto di Struttura della Materia (CNR-ISM), Area della Ricerca di Roma Tor Vergata, Via del Fosso del Cavaliere, 100-00133 Roma, Italy
| | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
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Nakamura M, Yang SJ, Lin KC, Kasai T, Che DC, Lombardi A, Palazzetti F, Aquilanti V. Stereodirectional images of molecules oriented by a variable-voltage hexapolar field: Fragmentation channels of 2-bromobutane electronically excited at two photolysis wavelengths. J Chem Phys 2017; 147:013917. [DOI: 10.1063/1.4981025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Shiun-Jr Yang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Dock-Chil Che
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Andrea Lombardi
- Università di Perugia, Dipartimento di Chimica, Biologia e Biotecnologie, 06123 Perugia, Italy
| | - Federico Palazzetti
- Università di Perugia, Dipartimento di Chimica, Biologia e Biotecnologie, 06123 Perugia, Italy
| | - Vincenzo Aquilanti
- Università di Perugia, Dipartimento di Chimica, Biologia e Biotecnologie, 06123 Perugia, Italy
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, 00016 Rome, Italy
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15
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Aquilanti V, Coutinho ND, Carvalho-Silva VH. Kinetics of low-temperature transitions and a reaction rate theory from non-equilibrium distributions. Philos Trans A Math Phys Eng Sci 2017; 375:rsta.2016.0201. [PMID: 28320904 PMCID: PMC5360900 DOI: 10.1098/rsta.2016.0201] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/14/2016] [Indexed: 05/14/2023]
Abstract
This article surveys the empirical information which originated both by laboratory experiments and by computational simulations, and expands previous understanding of the rates of chemical processes in the low-temperature range, where deviations from linearity of Arrhenius plots were revealed. The phenomenological two-parameter Arrhenius equation requires improvement for applications where interpolation or extrapolations are demanded in various areas of modern science. Based on Tolman's theorem, the dependence of the reciprocal of the apparent activation energy as a function of reciprocal absolute temperature permits the introduction of a deviation parameter d covering uniformly a variety of rate processes, from those where quantum mechanical tunnelling is significant and d < 0, to those where d > 0, corresponding to the Pareto-Tsallis statistical weights: these generalize the Boltzmann-Gibbs weight, which is recovered for d = 0. It is shown here how the weights arise, relaxing the thermodynamic equilibrium limit, either for a binomial distribution if d > 0 or for a negative binomial distribution if d < 0, formally corresponding to Fermion-like or Boson-like statistics, respectively. The current status of the phenomenology is illustrated emphasizing case studies; specifically (i) the super-Arrhenius kinetics, where transport phenomena accelerate processes as the temperature increases; (ii) the sub-Arrhenius kinetics, where quantum mechanical tunnelling propitiates low-temperature reactivity; (iii) the anti-Arrhenius kinetics, where processes with no energetic obstacles are rate-limited by molecular reorientation requirements. Particular attention is given for case (i) to the treatment of diffusion and viscosity, for case (ii) to formulation of a transition rate theory for chemical kinetics including quantum mechanical tunnelling, and for case (iii) to the stereodirectional specificity of the dynamics of reactions strongly hindered by the increase of temperature.This article is part of the themed issue 'Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'.
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Affiliation(s)
- Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
- Instituto de Física, Universidade Federal da Bahia, 40210 Salvador, Brazil
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, 00016 Rome, Italy
| | - Nayara Dantas Coutinho
- Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970 Brasília, Brazil
| | - Valter Henrique Carvalho-Silva
- Grupo de Química Teórica e Estrutural de Anápolis, Campus de Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, CP 459, 75001-970 Anápolis, GO, Brazil
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16
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Carvalho-Silva VH, Aquilanti V, de Oliveira HCB, Mundim KC. Deformed transition-state theory: Deviation from Arrhenius behavior and application to bimolecular hydrogen transfer reaction rates in the tunneling regime. J Comput Chem 2016; 38:178-188. [PMID: 27859380 DOI: 10.1002/jcc.24529] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 09/24/2016] [Accepted: 10/10/2016] [Indexed: 12/14/2022]
Abstract
A formulation is presented for the application of tools from quantum chemistry and transition-state theory to phenomenologically cover cases where reaction rates deviate from Arrhenius law at low temperatures. A parameter d is introduced to describe the deviation for the systems from reaching the thermodynamic limit and is identified as the linearizing coefficient in the dependence of the inverse activation energy with inverse temperature. Its physical meaning is given and when deviation can be ascribed to quantum mechanical tunneling its value is calculated explicitly. Here, a new derivation is given of the previously established relationship of the parameter d with features of the barrier in the potential energy surface. The proposed variant of transition state theory permits comparison with experiments and tests against alternative formulations. Prescriptions are provided and implemented to three hydrogen transfer reactions: CH4 + OH → CH3 + H2 O, CH3 Cl + OH → CH2 Cl + H2 O and H2 + CN → H + HCN, widely investigated both experimentally and theoretically. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Valter H Carvalho-Silva
- Grupo de Química Teórica e Estrutural de Anápolis, Unidade Universitária de Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, P.O. Box 459, 75001-970, Anápolis, GO, Brazil
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy. Instituto de Física, Universidade Federal da Bahia, 40210, Salvador, Brazil.,Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, 00016, Rome, Italy
| | - Heibbe C B de Oliveira
- Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970, Brasília, Brazil
| | - Kleber C Mundim
- Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970, Brasília, Brazil
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17
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Nakamura M, Yang SJ, Tsai PY, Kasai T, Lin KC, Che DC, Lombardi A, Palazzetti F, Aquilanti V. Hexapole-Oriented Asymmetric-Top Molecules and Their Stereodirectional Photodissociation Dynamics. J Phys Chem A 2016; 120:5389-98. [PMID: 27139246 DOI: 10.1021/acs.jpca.6b02410] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular orientation is a fundamental requisite in the study of stereodirected dynamics of collisional and photoinitiated processes. In this past decade, variable hexapolar electric filters have been developed and employed for the rotational-state selection and the alignment of molecules of increasing complexity, for which the main difficulties are their mass, their low symmetry, and the very dense rotational manifold. In this work, for the first time, a complex molecule such as 2-bromobutane, an asymmetric top containing a heavy atom (the bromine), was successfully oriented by a weak homogeneous field placed downstream from the hexapolar filter. Efficiency of the orientation was characterized experimentally, by combining time-of-flight measurements and a slice-ion-imaging detection technique. The application is described to the photodissociation dynamics of the oriented 2-bromobutane, which was carried out at a laser wavelength of 234 nm, corresponding to the breaking of the C-Br bond. The Br photofragment is produced in both the ground Br ((2)P3/2) and the excited Br ((2)P1/2) electronic states, and both channels are studied by the slice imaging technique, revealing new features in the velocity and angular distributions with respect to previous investigations on nonoriented molecules.
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Affiliation(s)
- Masaaki Nakamura
- Department of Chemistry, National Taiwan University , Taipei, Taiwan
| | - Shiun-Jr Yang
- Department of Chemistry, National Taiwan University , Taipei, Taiwan
| | - Po-Yu Tsai
- Department of Chemistry, National Taiwan University , Taipei, Taiwan.,Department of Chemistry, National Chung-Hsing University , Taichung, Taiwan
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University , Taipei, Taiwan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan University , Taipei, Taiwan.,Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei, Taiwan
| | - Dock-Chil Che
- Graduate School of Science, Department of Chemistry, Osaka University , Osaka, Japan
| | - Andrea Lombardi
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Perugia, Italy
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Perugia, Italy.,Scuola Normale Superiore , Pisa, Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Perugia, Italy.,Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia , 00016 Roma, Italy.,Insituto de Fìsica, Universidade Federal da Bahia , Salvador, Brazil
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18
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Coutinho ND, Aquilanti V, Silva VHC, Camargo AJ, Mundim KC, de Oliveira HCB. Stereodirectional Origin of anti-Arrhenius Kinetics for a Tetraatomic Hydrogen Exchange Reaction: Born-Oppenheimer Molecular Dynamics for OH + HBr. J Phys Chem A 2016; 120:5408-17. [PMID: 27205872 DOI: 10.1021/acs.jpca.6b03958] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Among four-atom processes, the reaction OH + HBr → H2O + Br is one of the most studied experimentally: its kinetics has manifested an unusual anti-Arrhenius behavior, namely, a marked decrease of the rate constant as the temperature increases, which has intrigued theoreticians for a long time. Recently, salient features of the potential energy surface have been characterized and most kinetic aspects can be considered as satisfactorily reproduced by classical trajectory simulations. Motivation of the work reported in this paper is the investigation of the stereodirectional dynamics of this reaction as the prominent reason for the peculiar kinetics: we started in a previous Letter ( J. Phys. Chem. Lett. 2015 , 6 , 1553 - 1558 ) a first-principles Born-Oppenheimer "canonical" molecular dynamics approach. Trajectories are step-by-step generated on a potential energy surface quantum mechanically calculated on-the-fly and are thermostatically equilibrated to correspond to a specific temperature. Here, refinements of the method permitted a major increase of the number of trajectories and the consideration of four temperatures -50, +200, +350, and +500 K, for which the sampling of initial conditions allowed us to characterize the stereodynamical effect. The role is documented of the adjustment of the reactants' mutual orientation to encounter the entrance into the "cone of acceptance" for reactivity. The aperture angle of this cone is dictated by a range of directions of approach compatible with the formation of the specific HOH angle of the product water molecule; and consistently the adjustment is progressively less effective the higher the kinetic energy. Qualitatively, this emerging picture corroborates experiments on this reaction, involving collisions of aligned and oriented molecular beams, and covering a range of energies higher than the thermal ones. The extraction of thermal rate constants from this molecular dynamics approach is discussed and the systematic sampling of the canonical ensemble is indicated as needed for quantitative comparison with the kinetic experiments.
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Affiliation(s)
- Nayara D Coutinho
- Instituto de Química, Universidade de Brasília , 4478, 70904-970 Brasília, Brazil
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Via Elce di Sotto 8, 06123, Perugia, Italy.,Instituto de Física, Universidade Federal da Bahia , 40210 Salvador, Brazil.,Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche , 00016 Rome, Italy
| | - Valter H C Silva
- Grupo de Química Teórica e Estrutural de Anápolis, Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás , 0459, 75001-970 Anápolis, GO Brazil
| | - Ademir J Camargo
- Grupo de Química Teórica e Estrutural de Anápolis, Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás , 0459, 75001-970 Anápolis, GO Brazil
| | - Kleber C Mundim
- Instituto de Química, Universidade de Brasília , 4478, 70904-970 Brasília, Brazil
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19
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De Fazio D, Cavalli S, Aquilanti V. Benchmark Quantum Mechanical Calculations of Vibrationally Resolved Cross Sections and Rate Constants on ab Initio Potential Energy Surfaces for the F + HD Reaction: Comparisons with Experiments. J Phys Chem A 2016; 120:5288-99. [PMID: 27186680 DOI: 10.1021/acs.jpca.6b01471] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dario De Fazio
- Istituto di Struttura della
Materia, Consiglio Nazionale delle Ricerche, 00016 Roma, Italy
| | - Simonetta Cavalli
- Dipartimento di Chimica,
Biologia e Biotecnologie, Università di Perugia, 06123 Perugia, Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica,
Biologia e Biotecnologie, Università di Perugia, 06123 Perugia, Italy
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20
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Albernaz AF, Aquilanti V, Barreto PRP, Caglioti C, Cruz ACPS, Grossi G, Lombardi A, Palazzetti F. Interactions of Hydrogen Molecules with Halogen-Containing Diatomics from Ab Initio Calculations: Spherical-Harmonics Representation and Characterization of the Intermolecular Potentials. J Phys Chem A 2016; 120:5315-24. [DOI: 10.1021/acs.jpca.6b01718] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alessandra F. Albernaz
- Instituto
de Física, Universidade de Brasília, CP04455, Brasília, Distrito Federal CEP 70919-970, Brazil
| | - Vincenzo Aquilanti
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, via Elce
di Sotto 8, 06123 Perugia, Italy
| | - Patricia R. P. Barreto
- Instituto Nacional de Pesquisas Espaciais (INPE)/MCT, Laboratòrio Associado de Plasma (LAP), CP515, São José
dos Campos, São Paulo CEP 12247-970, Brazil
| | - Concetta Caglioti
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, via Elce
di Sotto 8, 06123 Perugia, Italy
| | - Ana Claudia P. S. Cruz
- Instituto Nacional de Pesquisas Espaciais (INPE)/MCT, Laboratòrio Associado de Plasma (LAP), CP515, São José
dos Campos, São Paulo CEP 12247-970, Brazil
| | - Gaia Grossi
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, via Elce
di Sotto 8, 06123 Perugia, Italy
| | - Andrea Lombardi
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, via Elce
di Sotto 8, 06123 Perugia, Italy
| | - Federico Palazzetti
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, via Elce
di Sotto 8, 06123 Perugia, Italy
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126, Pisa, Italy
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21
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Cappelletti D, Aquilanti V, Bartocci A, Nunzi F, Tarantelli F, Belpassi L, Pirani F. Interaction of O2 with CH4, CF4, and CCl4 by Molecular Beam Scattering Experiments and Theoretical Calculations. J Phys Chem A 2016; 120:5197-207. [PMID: 26938313 DOI: 10.1021/acs.jpca.6b00948] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gas phase collisions of O2 by CH4, CF4, and CCl4 have been investigated with the molecular beam technique by measuring both the integral cross section value, Q, and its dependence on the collision velocity, v. The adopted experimental conditions have been appropriate to resolve the oscillating "glory" pattern, a quantum interference effect controlled by the features of the intermolecular interaction, for all the three case studies. The analysis of the Q(v) data, performed by adopting a suitable representation of the intermolecular potential function, provided the basic features of the anisotropic potential energy surfaces at intermediate and large separation distances and information on the relative role of the physically relevant types of contributions to the global interaction. The present work demonstrates that while O2-CH4 and O2-CF4 are basically bound through the balance between size (Pauli) repulsion and dispersion attraction, an appreaciable intermolecular bond stabilization by charge transfer is operative in O2-CCl4. Ab initio calculations of the strength of the interaction, coupled with detailed analysis of electronic charge displacement promoted by the formation of the dimer, fully rationalizes the experimental findings. This investigation indicates that the interactions of O2, when averaged over its relative orientations, are similar to that of a noble gas (Ng), specifically Ar. We also show that the binding energy in the basic configurations of the prototypical Ng-CF4,CCl4 systems [ Cappelletti , D. ; Chem. Eur. J. 2015 , 21 , 6234 - 6240 ] can be reconstructed by using the interactions in Ng-F and Ng-Cl systems, previously characterized by molecular beam scattering experiments of state-selected halogen atom beams. This information is fundamental to approach the modeling of the weak intermolecular halogen bond. On the basis of the electronic polarizability, this also confirms [ Aquilanti , V. ; Angew. Chem., Int. Ed. 2005 , 44 , 2356 - 2360 ] that O2 can be taken as a proper reference partner for simulating the behavior of some basic noncovalent components of the interactions involving water. Present results are of fundamental relevance to build up the force field controlling the hydrophobic behavior of prototypical apolar CX4 (X = H, F, Cl) molecules.
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Affiliation(s)
- David Cappelletti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Alessio Bartocci
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Francesca Nunzi
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Via Elce di Sotto 8, 06123 Perugia, Italy.,CNR-Istituto di Scienze e Tecnologie Molecolari, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Francesco Tarantelli
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Via Elce di Sotto 8, 06123 Perugia, Italy.,CNR-Istituto di Scienze e Tecnologie Molecolari, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Leonardo Belpassi
- CNR-Istituto di Scienze e Tecnologie Molecolari, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Via Elce di Sotto 8, 06123 Perugia, Italy
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22
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Lombardi A, Palazzetti F, Aquilanti V, Li HK, Tsai PY, Kasai T, Lin KC. Rovibrationally Excited Molecules on the Verge of a Triple Breakdown: Molecular and Roaming Mechanisms in the Photodecomposition of Methyl Formate. J Phys Chem A 2016; 120:5155-62. [DOI: 10.1021/acs.jpca.6b00723] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Andrea Lombardi
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce
di Sotto 8, 06123 Perugia, Italy
| | - Federico Palazzetti
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce
di Sotto 8, 06123 Perugia, Italy
| | - Vincenzo Aquilanti
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce
di Sotto 8, 06123 Perugia, Italy
- Istituto
di Struttura della Materia, Consiglio Nazionale delle Ricerche, Rome, Italy
- Instituto
de Fisica, Universidade Federal da Bahia, Salvador, Brazil
| | - Hou-Kuan Li
- Department
of Chemistry, National Taiwan University, Taipei 106, Taiwan
| | - Po-Yu Tsai
- Department
of Chemistry, National Taiwan University, Taipei 106, Taiwan
| | - Toshio Kasai
- Department
of Chemistry, National Taiwan University, Taipei 106, Taiwan
| | - King-Chuen Lin
- Department
of Chemistry, National Taiwan University, Taipei 106, Taiwan
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23
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Nakamura M, Tsai PY, Kasai T, Lin KC, Palazzetti F, Lombardi A, Aquilanti V. Dynamical, spectroscopic and computational imaging of bond breaking in photodissociation: roaming and role of conical intersections. Faraday Discuss 2015; 177:77-98. [PMID: 25625792 DOI: 10.1039/c4fd00174e] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Recent experimental and theoretical advances in the study of the dissociation of excited molecules are revealing unexpected mechanisms, when their outcomes are tackled by combining (i) space-time ion imaging of translational features, with (ii) spectroscopic probing of rotational and vibrational distributions; crucial is the assistance of (iii) the quantum chemistry of structural investigations of rearrangements of chemical bonds, and of (iv) the simulations of molecular dynamics to follow the evolution of selective bond stretching and breaking. Here we present results of such an integrated approach to methyl formate, HCOOCH3, the simplest of esters; the main focus is on the rotovibrationally excited CO (v=1) product and in general on the energy distribution in the fragments. Previous laser studies of dissociation into CO and CH3OH at a sequence of various wavelengths discovered signatures of a roaming mechanism by the late arrival of CO (v=0) products in time-of-flight ion imaging. Subsequent detailed investigations as a function of excitation energy provided the assessment of the threshold, which opens for triple breakdown into CO and further fragments H and CH3O, as spectroscopically characterized by ion imaging and FTIR respectively. Accompanying quantum mechanical electronic structure calculations and classical molecular dynamics simulations clarify the origin of these fragments through "roaming" pathways involving incipient radical intermediates at energies below the triple fragmentation threshold: a specific role is played by nonadiabatic transitions at a conical intersection between ground and excited states; alternative pathways focalize our attention to regions of the potential energy surfaces other than those in the neighbourhoods of saddle points along minimum energy paths: eventually this leads us to look for avenues in reaction kinetics beyond those of venerable transition state theories.
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Affiliation(s)
- Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan.
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24
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Editor U, Carvalho VH, Aquilanti V, Oliveira HCB, Mundim KC. Deformed Transition State Theory: Inclusion of the Tunneling Effect by Euler Exponential, Limit of Validity and Description of Bimolecular Reactions. ACTA ACUST UNITED AC 2015. [DOI: 10.19142/rpq.v9i18.306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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25
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Roncaratti LF, Leal LA, Pirani F, Aquilanti V, e Silva GM, Gargano R. Chirality of weakly bound complexes: the potential energy surfaces for the hydrogen-peroxide-noble-gas interactions. J Chem Phys 2015; 141:134309. [PMID: 25296808 DOI: 10.1063/1.4897136] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We consider the analytical representation of the potential energy surfaces of relevance for the intermolecular dynamics of weakly bound complexes of chiral molecules. In this paper we study the H2O2-Ng (Ng=He, Ne, Ar, Kr, and Xe) systems providing the radial and the angular dependence of the potential energy surface on the relative position of the Ng atom. We accomplish this by introducing an analytical representation which is able to fit the ab initio energies of these complexes in a wide range of geometries. Our analysis sheds light on the role that the enantiomeric forms and the symmetry of the H2O2 molecule play on the resulting barriers and equilibrium geometries. The proposed theoretical framework is useful to study the dynamics of the H2O2 molecule, or other systems involving O-O and S-S bonds, interacting by non-covalent forces with atoms or molecules and to understand how the relative orientation of the O-H bonds changes along collisional events that may lead to a hydrogen bond formation or even to selectivity in chemical reactions.
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Affiliation(s)
- L F Roncaratti
- Instituto de Física, Universidade de Brasília, 70910 Brasília, Brazil
| | - L A Leal
- Instituto de Física, Universidade de Brasília, 70910 Brasília, Brazil
| | - F Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, 06123 Perugia, Italy
| | - V Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, 06123 Perugia, Italy
| | - G M e Silva
- Instituto de Física, Universidade de Brasília, 70910 Brasília, Brazil
| | - R Gargano
- Instituto de Física, Universidade de Brasília, 70910 Brasília, Brazil
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26
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Coutinho ND, Silva VHC, de Oliveira HCB, Camargo AJ, Mundim KC, Aquilanti V. Stereodynamical Origin of Anti-Arrhenius Kinetics: Negative Activation Energy and Roaming for a Four-Atom Reaction. J Phys Chem Lett 2015; 6:1553-8. [PMID: 26263312 DOI: 10.1021/acs.jpclett.5b00384] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The OH + HBr → H2O + Br reaction, prototypical of halogen-atom liberating processes relevant to mechanisms for atmospheric ozone destruction, attracted frequent attention of experimental chemical kinetics: the nature of the unusual reactivity drop from low to high temperatures eluded a variety of theoretical efforts, ranking this one among the most studied four-atom reactions. Here, inspired by oriented molecular-beams experiments, we develop a first-principles stereodynamical approach. Thermalized sets of trajectories, evolving on a multidimensional potential energy surface quantum mechanically generated on-the-fly, provide a map of most visited regions at each temperature. Visualizations of rearrangements of bonds along trajectories and of the role of specific angles of reactants' mutual approach elucidate the mechanistic change from the low kinetic energy regime (where incident reactants reorient to find the propitious alignment leading to reaction) to high temperature (where speed hinders adjustment of directionality and roaming delays reactivity).
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Affiliation(s)
- Nayara D Coutinho
- †Unidade Universitária de Ciências Exatas e Tecnológicas, 75001-970, Anápolis, and Unidade de Ipameri, Ipameri, Universidade Estadual de Goiás, 75780-000 Goiás, Brazil
- ‡Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970 Brasília, Brazil
| | - Valter H C Silva
- †Unidade Universitária de Ciências Exatas e Tecnológicas, 75001-970, Anápolis, and Unidade de Ipameri, Ipameri, Universidade Estadual de Goiás, 75780-000 Goiás, Brazil
| | - Heibbe C B de Oliveira
- ‡Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970 Brasília, Brazil
| | - Ademir J Camargo
- †Unidade Universitária de Ciências Exatas e Tecnológicas, 75001-970, Anápolis, and Unidade de Ipameri, Ipameri, Universidade Estadual de Goiás, 75780-000 Goiás, Brazil
| | - Kleber C Mundim
- ‡Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970 Brasília, Brazil
| | - Vincenzo Aquilanti
- §Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
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Dhoke K, Zanni M, Harbola U, Venkatraman RK, Arunan E, Lin KC, Nenov A, Skelton J, Miller RJD, Hirst JD, Aquilanti V, Helliwell JR, Keshavamurthy S, Ramesh S, Ashfold M, Pallipurath A, Roy Chowdhury P, Mukhopadhyay S, E D J, Medhi H, Goswami D, Halder P, Junge W, Hariharan M, Singh SK, Umapathy S, Lakshmannam A, Meedom Nielsen M, Aravamudhan S, Deckert V, Ghiggino K, Tominaga K, Edwards A. Dynamics of chemical bond: general discussion. Faraday Discuss 2015; 177:121-54. [DOI: 10.1039/c5fd90016f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Cavalli S, Aquilanti V, Mundim KC, De Fazio D. Theoretical reaction kinetics astride the transition between moderate and deep tunneling regimes: the F + HD case. J Phys Chem A 2014; 118:6632-41. [PMID: 24893210 DOI: 10.1021/jp503463w] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
For the reaction between F and HD, giving HF + D and DF + H, the rate constants, obtained from rigorous quantum scattering calculations at temperatures ranging from 350 K down to 100 K, show deviations from the Arrhenius behavior that have been interpreted in terms of tunneling of either H or D atoms through a potential energy barrier. The interval of temperature investigated extends from above to below a crossover value Tc, a transition temperature separating the moderate and deep quantum tunneling regimes. Below Tc, the rate of the H or D exchange reaction is controlled by the prevalence of tunneling over the thermal activation mechanism. In this temperature range, Bell's early treatment of quantum tunneling, based on a semiclassical approximation for the barrier permeability, provides a reliable tool to quantitatively account for the contribution of the tunneling effect. This treatment is here applied for extracting from rate constants properties of the effective tunneling path, such as the activation barrier height and width. We show that this is a way of parametrizing the dependence of the apparent activation energy on temperature useful for both calculated and experimental rate constants in an ample interval of temperature, from above to below Tc, relevant for modelization of astrophysical and in general very low-temperature environments.
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Affiliation(s)
- S Cavalli
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , 06123 Perugia, Italy
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Palazzetti F, Maciel GS, Kanda K, Nakamura M, Che DC, Kasai T, Aquilanti V. Control of conformers combining cooling by supersonic expansion of seeded molecular beams with hexapole selection and alignment: experiment and theory on 2-butanol. Phys Chem Chem Phys 2014; 16:9866-75. [PMID: 24413635 DOI: 10.1039/c3cp54475c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selection and alignment of rotamers and, more in general, of conformers in the gas phase is a challenge that we tackle experimentally by supersonic expansion of seeded molecular beams and hexapolar electrostatic fields with quadrupole mass detection. The studied system involves the nine conformers of the asymmetric-top molecule 2-butanol, which coexist because of nearly free rotations around a CC and a CO bond. From the measured time-of-flight of a 2-butanol supersonic molecular beam seeded in either He or Ar, the corresponding velocity distributions are obtained. The different nature and masses of the seeding gas decrease selectively the vibrational temperature and determine the population of the conformers, which is assessed on the basis of their statistical distribution, derived from high level accompanying quantum mechanical calculations. The use of a hexapolar electrostatic field permits us to induce a variation of the population distribution as a function of the applied voltage and of the selective focusing and alignment of the conformers. A technique, recently developed for treating asymmetric tops and involving extensive trajectory simulations, is applied to obtain the link between the focusing curves, i.e. the dependence of the beam intensity on the hexapole voltage, and the conformers' populations and alignment. Perspectives are provided for photo- and stereo-dynamics experiments, particularly appealing also on account that 2-butanol is the simplest chiral alcohol.
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Tsai PY, Chao MH, Kasai T, Lin KC, Lombardi A, Palazzetti F, Aquilanti V. Roads leading to roam. Role of triple fragmentation and of conical intersections in photochemical reactions: experiments and theory on methyl formate. Phys Chem Chem Phys 2014; 16:2854-65. [DOI: 10.1039/c3cp53792g] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kasai T, Che DC, Okada M, Tsai PY, Lin KC, Palazzetti F, Aquilanti V. Directions of chemical change: experimental characterization of the stereodynamics of photodissociation and reactive processes. Phys Chem Chem Phys 2014; 16:9776-90. [DOI: 10.1039/c4cp00464g] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Silva VH, Aquilanti V, de Oliveira HC, Mundim KC. Uniform description of non-Arrhenius temperature dependence of reaction rates, and a heuristic criterion for quantum tunneling vs classical non-extensive distribution. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.10.051] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Alagia M, Aquilanti V, Ascenzi D, Balucani N, Cappelletti D, Cartechini L, Casavecchia P, Pirani F, Sanchini G, Volpi GG. Magnetic Analysis of Supersonic Beams of Atomic Oxygen, Nitrogen, and Chlorine Generated from a Radio-Frequency Discharge. Isr J Chem 2013. [DOI: 10.1002/ijch.199700038] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Krasilnikov MB, Popov RS, Roncero O, De Fazio D, Cavalli S, Aquilanti V, Vasyutinskii OS. Polarization of molecular angular momentum in the chemical reactions Li + HF and F + HD. J Chem Phys 2013; 138:244302. [DOI: 10.1063/1.4809992] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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De Fazio D, de Castro-Vitores M, Aguado A, Aquilanti V, Cavalli S. The He + H2+ → HeH+ + H reaction: ab initio studies of the potential energy surface, benchmark time-independent quantum dynamics in an extended energy range and comparison with experiments. J Chem Phys 2013; 137:244306. [PMID: 23277935 DOI: 10.1063/1.4772651] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work we critically revise several aspects of previous ab initio quantum chemistry studies [P. Palmieri et al., Mol. Phys. 98, 1835 (2000); C. N. Ramachandran et al., Chem. Phys. Lett. 469, 26 (2009)] of the HeH(2)(+) system. New diatomic curves for the H(2)(+) and HeH(+) molecular ions, which provide vibrational frequencies at a near spectroscopic level of accuracy, have been generated to test the quality of the diatomic terms employed in the previous analytical fittings. The reliability of the global potential energy surfaces has also been tested performing benchmark quantum scattering calculations within the time-independent approach in an extended interval of energies. In particular, the total integral cross sections have been calculated in the total collision energy range 0.955-2.400 eV for the scattering of the He atom by the ortho- and para-hydrogen molecular ion. The energy profiles of the total integral cross sections for selected vibro-rotational states of H(2)(+) (v = 0,...,5 and j = 1,...,7) show a strong rotational enhancement for the lower vibrational states which becomes weaker as the vibrational quantum number increases. Comparison with several available experimental data is presented and discussed.
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Affiliation(s)
- Dario De Fazio
- Istituto di Metodologie Inorganiche e dei Plasmi - C.N.R., 00016 Roma, Italy.
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Coletti C, Calderini D, Aquilanti V. d-Dimensional Kepler–Coulomb Sturmians and Hyperspherical Harmonics as Complete Orthonormal Atomic and Molecular Orbitals. Proceedings of MEST 2012: Exponential Type Orbitals for Molecular Electronic Structure Theory 2013. [DOI: 10.1016/b978-0-12-411544-6.00005-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Barreto PR, Albernaz AF, Capobianco A, Palazzetti F, Lombardi A, Grossi G, Aquilanti V. Potential energy surfaces for interactions of H2O with H2, N2 and O2: A hyperspherical harmonics representation, and a minimal model for the H2O–rare-gas-atom systems. COMPUT THEOR CHEM 2012. [DOI: 10.1016/j.comptc.2011.12.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Krasil’nikov MB, Vasyutinskii OS, De Fazio D, Cavalli S, Aquilanti V. Vector correlations in the F + HD reaction. Russ J Phys Chem B 2012. [DOI: 10.1134/s1990793112050065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Aquilanti V, Mundim K, Cavalli S, De Fazio D, Aguilar A, Lucas J. Exact activation energies and phenomenological description of quantum tunneling for model potential energy surfaces. The F+H2 reaction at low temperature. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2011.05.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Aquilanti V, Liuti G, Luzzatti E, Vecchio-Cattivi F, Volpi GG. Production and Detection of an Energy Selected Beam of Hydrogen Atoms in the Range 0.01—0.20 eV. Z PHYS CHEM 2011. [DOI: 10.1524/zpch.1972.79.3_4.200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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De Fazio D, Lucas JM, Aquilanti V, Cavalli S. Exploring the accuracy level of new potential energy surfaces for the F + HD reactions: from exact quantum rate constants to the state-to-state reaction dynamics. Phys Chem Chem Phys 2011; 13:8571-82. [DOI: 10.1039/c0cp02738c] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Elango M, Maciel GS, Palazzetti F, Lombardi A, Aquilanti V. Quantum chemistry of C(3)H(6)O molecules: structure and stability, isomerization pathways, and chirality changing mechanisms. J Phys Chem A 2010; 114:9864-74. [PMID: 20575571 DOI: 10.1021/jp1034618] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electronic structure calculations were carried out to study the various isomers of formula C(3)H(6)O, as a part of our current quantum chemical and dynamical approaches to intra- and intermolecular kinetics for the C(n)H(2n)O (n = 1, 2, 3) molecules. The usefulness of the GRRM (global reaction route mapping) program developed by Ohno and Maeda in predicting the structure of all isomers and of the transition states connecting them is fully exploited. All the isomers are identified as local minima on the MP2/CC-PVDZ potential energy surface. Acetone is the most stable isomer. In increasing order of stability the others are propanal, 2-propenol, 1-propenol, allyl alcohol, methyl vinyl ether, cyclopropanol, propylene oxide, and oxetane. Various isomerization paths connecting them are identified. All the transition states are fully characterized using intrinsic reaction coordinate calculations. The isomerization reactions may proceed through a single step or involve an intermediate species which is either a carbene or a diradical. Special attention is devoted to propylene oxide, a favorite molecule in current photochemical and stereodynamical studies because of its chiral nature. It is a rigid molecule, and chirality switching is found to be supported by its isomers. Two different chirality switching mechanisms which are assisted by propanal and allyl alcohol are presented.
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Affiliation(s)
- Munusamy Elango
- Dipartimento di Chimica, Universita di Perugia, 06123 Perugia, Italy
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Aquilanti V, Mundim KC, Elango M, Kleijn S, Kasai T. Temperature dependence of chemical and biophysical rate processes: Phenomenological approach to deviations from Arrhenius law. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.08.035] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Che DC, Palazzetti F, Okuno Y, Aquilanti V, Kasai T. Electrostatic hexapole state-selection of the asymmetric-top molecule propylene oxide. J Phys Chem A 2010; 114:3280-6. [PMID: 20099859 DOI: 10.1021/jp909553t] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rotational state-selection of the asymmetric-top molecule propylene oxide was carried out using an electrostatic hexapole field of 85-cm length. Molecular beam intensities were monitored by a quadrupole mass spectrometer. It was found that beam intensities of molecular beams for pure propylene oxide and those seeded in He and in Ar increased with increasing hexapole voltages. The hexapole voltage dependence of the beam intensity, which is called the focusing curve, was interpreted by computer simulation of the trajectories of molecules in the hexapolar field due to the Stark effect, as a function of rotational temperatures of molecular beams. The calculated best fit focusing curves, when compared with the experimental results, demonstrated that the rotational temperatures, associated with the distribution of states of a given rotational angular momentum J, are similar to the translational temperatures. It was found that the M = 0 states (where M is the projection of J along the direction of the electrostatic field) and negative values of the pseudoquantum number tau of propylene oxide can be selected using our experimental setup. These results suggest that the hexapole electric field is a tool even for the selection of rotational and orientation states of asymmetric-top molecules.
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Affiliation(s)
- Dock-Chil Che
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan.
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Aquilanti V. List of Publications of Vincenzo Aquilanti. J Phys Chem A 2009; 113:14193-205. [DOI: 10.1021/jp9097777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Nishiyama M, Kleijn S, Aquilanti V, Kasai T. Temperature dependence of respiration rates of leaves, 18O-experiments and super-Arrhenius kinetics. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Affiliation(s)
- Roger W. Anderson
- Department of Chemistry, University of California, Santa Cruz, California 95064
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Università degli Studi di Perugia, via Elce di Sotto 8, 06126 Perugia, Italy
| | - Annalisa Marzuoli
- Dipartimento di Fisica Nucleare e Teorica, Università degli Studi di Pavia and INFN, Sezione di Pavia, via A. Bassi 6, 27100 Pavia, Italy
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Skouteris D, De Fazio D, Cavalli S, Aquilanti V. Quantum Stereodynamics for the Two Product Channels of the F + HD Reaction from the Complete Scattering Matrix in the Stereodirected Representation. J Phys Chem A 2009; 113:14807-12. [PMID: 19761272 DOI: 10.1021/jp904972n] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D. Skouteris
- Dipartimento di Matematica e Informatica, Università degli Studi di Perugia, 06123 Perugia, Italy, Istituto di Metodologie Inorganiche e dei Plasmi, CNR, 00016 Roma, Italy, and Dipartimento di Chimica, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - D. De Fazio
- Dipartimento di Matematica e Informatica, Università degli Studi di Perugia, 06123 Perugia, Italy, Istituto di Metodologie Inorganiche e dei Plasmi, CNR, 00016 Roma, Italy, and Dipartimento di Chimica, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - S. Cavalli
- Dipartimento di Matematica e Informatica, Università degli Studi di Perugia, 06123 Perugia, Italy, Istituto di Metodologie Inorganiche e dei Plasmi, CNR, 00016 Roma, Italy, and Dipartimento di Chimica, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - V. Aquilanti
- Dipartimento di Matematica e Informatica, Università degli Studi di Perugia, 06123 Perugia, Italy, Istituto di Metodologie Inorganiche e dei Plasmi, CNR, 00016 Roma, Italy, and Dipartimento di Chimica, Università degli Studi di Perugia, 06123 Perugia, Italy
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