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Reja D, Kumar S. He + +N 2 Charge Transfer Reaction: An Ab initio Analysis. Chemphyschem 2023; 24:e202200880. [PMID: 37071387 DOI: 10.1002/cphc.202200880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 04/16/2023] [Accepted: 04/17/2023] [Indexed: 04/19/2023]
Abstract
An ab initio analysis on the involved potential energy surfaces is presented for the investigation of the charge transfer mechanism for the He+ +N2 system. At high collision energy, as many as seven low-lying electronic states are observed to be involved in the charge transfer mechanism. Potential energy surfaces for these low-lying electronic states have been computed in the Jacobi scattering coordinates, applying multireference configuration interaction level of theory and aug-cc-pVQZ basis sets. Asymptotes for the ground and various excited states are assigned to mark the entrance (He+ +N2 ) and charge transfer channels (He+N2 + ). Nonadiabatic coupling matrix elements and quasi-diabatic potential energy surfaces have been computed for all seven states to rationalize the available experimental data on the charge transfer processes and to facilitate dynamics studies.
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Affiliation(s)
- Deboki Reja
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Sanjay Kumar
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
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Urbain X, Dochain A, Marion R, Launoy T, Loreau J. Photodissociation as a probe of the H 3+ avoided crossing seam. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20180399. [PMID: 31378172 PMCID: PMC6710895 DOI: 10.1098/rsta.2018.0399] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/20/2019] [Indexed: 06/10/2023]
Abstract
Experiments are conducted to investigate the role of the avoided crossing seam in the photodissociation of H3+. Three-dimensional imaging of dissociation products is used to determine the kinetic energy release and branching ratio among the fragmentation channels. Vibrational distributions are measured by dissociative charge transfer of H2+ products. It is found that the photodissociation of hot H3+ in the near-ultraviolet produces cold H2+, but hot H2. Modelling the wavepacket dynamics along the repulsive potential energy surface accounts for the repopulation of the ground potential energy surface. The role of the avoided crossing seam is emphasized and its importance for the astrophysically relevant charge transfer reactions underlined. This article is part of a discussion meeting issue 'Advances in hydrogen molecular ions: H3+, H5+ and beyond'.
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Affiliation(s)
- X. Urbain
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Chemin du Cyclotron 2, 1348 Louvain- la-Neuve, Belgium
| | - A. Dochain
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Chemin du Cyclotron 2, 1348 Louvain- la-Neuve, Belgium
| | - R. Marion
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Chemin du Cyclotron 2, 1348 Louvain- la-Neuve, Belgium
| | - T. Launoy
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Chemin du Cyclotron 2, 1348 Louvain- la-Neuve, Belgium
- Laboratoire de Chimie Quantique et Photophysique, Université Libre de Bruxelles, Av. F. Roosevelt 50, 1050 Brussels, Belgium
| | - J. Loreau
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Chemin du Cyclotron 2, 1348 Louvain- la-Neuve, Belgium
- Laboratoire de Chimie Quantique et Photophysique, Université Libre de Bruxelles, Av. F. Roosevelt 50, 1050 Brussels, Belgium
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Saheer VC, Kumar S. $$\hbox {H}^{+} + \hbox {O}_2$$
H
+
+
O
2
system revisited: four-state quasidiabatic potential energy surfaces and coupling potentials. J CHEM SCI 2018. [DOI: 10.1007/s12039-018-1531-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Mukherjee B, Mukhopadhyay D, Adhikari S, Baer M. Topological study of the H3++ molecular system: H3++ as a cornerstone for building molecules during the Big Bang. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1442940] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Bijit Mukherjee
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Kolkata, India
| | | | - Satrajit Adhikari
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Kolkata, India
| | - Michael Baer
- The Fritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem, Jerusalem, Israel
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Suárez J, Méndez L, Rabadán I. Nonadiabatic fragmentation of H2O+ and isotopomers. Wave packet propagation using ab initio wavefunctions. Phys Chem Chem Phys 2018; 20:28511-28522. [DOI: 10.1039/c8cp03725f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nonadiabatic fragmentation of excited water cations (and isotopomers) is studied by propagating wave packets on ab initio potential energy surfaces.
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Affiliation(s)
- Jaime Suárez
- Laboratorio Asociado al CIEMAT de Física Atómica y Molecular en Plasmas de Fusión
- Departamento de Química
- Universidad Autónoma de Madrid
- 28049-Madrid
- Spain
| | - L. Méndez
- Laboratorio Asociado al CIEMAT de Física Atómica y Molecular en Plasmas de Fusión
- Departamento de Química
- Universidad Autónoma de Madrid
- 28049-Madrid
- Spain
| | - I. Rabadán
- Laboratorio Asociado al CIEMAT de Física Atómica y Molecular en Plasmas de Fusión
- Departamento de Química
- Universidad Autónoma de Madrid
- 28049-Madrid
- Spain
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6
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Csehi A, Bende A, Halász GJ, Vibók Á, Das A, Mukhopadhyay D, Baer M. A tri-atomic Renner-Teller system entangled with Jahn-Teller conical intersections. J Chem Phys 2013; 138:024113. [PMID: 23320674 DOI: 10.1063/1.4773352] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The present study concentrates on a situation where a Renner-Teller (RT) system is entangled with Jahn-Teller (JT) conical intersections. Studies of this type were performed in the past for contours that surround the RT seam located along the collinear axis [see, for instance, G. J. Halász, Á. Vibók, R. Baer, and M. Baer, J. Chem. Phys. 125, 094102 (2006)]. The present study is characterized by planar contours that intersect the collinear axis, thus, forming a unique type of RT-non-adiabatic coupling terms (NACT) expressed in terms of Dirac-δ functions. Consequently, to calculate the required adiabatic-to-diabatic (mixing) angles, a new approach is developed. During this study we revealed the existence of a novel molecular parameter, η, which yields the coupling between the RT and the JT NACTs. This parameter was found to be a pure number η = 22/π (and therefore independent of any particular molecular system) and is designated as Renner-Jahn coupling parameter. The present study also reveals an unexpected result of the following kind: It is well known that each (complete) group of states, responsible for either the JT-effect or the RT-effect, forms a Hilbert space of its own. However, the entanglement between these two effects forms a third effect, namely, the RT/JT effect and the states that take part in it form a different Hilbert space.
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Affiliation(s)
- A Csehi
- Department of Information Technology, University of Debrecen, H-4010 Debrecen, P.O. Box 12, Hungary
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Das A, Sahoo T, Mukhopadhyay D, Adhikari S, Baer M. Dressed adiabatic and diabatic potentials to study conical intersections for F + H2. J Chem Phys 2012; 136:054104. [DOI: 10.1063/1.3679406] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Das A, Mukhopadhyay D, Adhikari S, Baer M. Renner-Teller intersections along the collinear axes of polyatomic molecules: H2CN as a case study. J Chem Phys 2010; 133:084107. [PMID: 20815560 DOI: 10.1063/1.3479399] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The tetra-atomic C(2)H(2)(+) cation is known to form Renner-Teller-type intersections along its collinear axis. Not too long ago, we studied the nonadiabatic coupling terms (NACTs) of this molecule [G. J. Halász et al., J. Chem. Phys. 126, 154309 (2007)] and revealed two kinds of intersections. (i) By employing one of the hydrogens as a test particle, we revealed the fact that indeed the corresponding (angular) NACTs produce topological (Berry) phases that are equal to 2pi, which is a result anticipated in the case of Renner-Teller intersections. (ii) However, to our big surprise, repeating this study when one of the atoms (in this case a hydrogen) is shifted from the collinear arrangement yields for the corresponding topological phase a value that equals pi (and not 2pi). In other words, shifting (even slightly) one of the atoms from the collinear arrangement causes the intersection to change its character and become a Jahn-Teller intersection. This somewhat unexpected novel result was later further analyzed and confirmed by other groups [e.g., T. Vertesi and R. Englman, J. Phys. B 41, 025102 (2008)]. The present article is devoted to another tetra-atomic molecule, namely, the H(2)CN molecule, which just like the C(2)H(2)(+) ion, is characterized by Renner-Teller intersections along its collinear axis. Indeed, we revealed the existence of Renner-Teller intersections along the collinear axis, but in contrast to the C(2)H(2)(+) case a shift of one atom from the collinear arrangement did not form Jahn-Teller intersections. What we found instead is that the noncollinear molecule was not affected by the shift and kept its Renner-Teller character. Another issue treated in this article is the extension of (the two-state) Berry (topological) phase to situations with numerous strongly interacting states. So far the relevance of the Berry phase was tested for systems characterized by two isolated interacting states, although it is defined for any number of interacting states [M. V. Berry, Proc. R. Soc. London, Ser. A 392, 45 (1984)]. We intend to show how to overcome this limitation and get a valid, fully justified definition of a Berry phase for an isolated system of any number of interacting states (as is expected).
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Affiliation(s)
- Anita Das
- Department of Chemistry, University of Calcutta, Kolkata 700 009, India
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Aguado A, Barragán P, Prosmiti R, Delgado-Barrio G, Villarreal P, Roncero O. A new accurate and full dimensional potential energy surface of H5+ based on a triatomics-in-molecules analytic functional form. J Chem Phys 2010; 133:024306. [DOI: 10.1063/1.3454658] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Paul AK, Adhikari S, Baer M. Space-time contours to treat intense field-dressed molecular states. J Chem Phys 2010; 132:034303. [PMID: 20095735 DOI: 10.1063/1.3282333] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this article we consider a molecular system exposed to an intense short-pulsed external field. It is a continuation of a previous publication [A. K. Paul, S. Adhikari, D. Mukhopadhyay et al., J. Phys. Chem. A 113, 7331 (2009)] in which a theory is presented that treats quantum effects due to nonclassical photon states (known also as Fock states). Since these states became recently a subject of intense experimental efforts we thought that they can be treated properly within the existing quantum formulation of dynamical processes. This was achieved by incorporating them in the Born-Oppenheimer (BO) treatment with time-dependent coefficients. The extension of the BO treatment to include the Fock states results in a formidable enhancement in numerical efforts expressed, in particular, in a significant increase in CPU time. In the present article we discuss an approach that yields an efficient and reliable approximation with only negligible losses in accuracy. The approximation is tested in detail for the dissociation process of H(2) (+) as caused by a laser field.
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Affiliation(s)
- Amit K Paul
- Department of Physical Chemistry, Indian Association for Cultivation of Science, Jadavpur, Kolkata 700 032, India
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11
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Al-Jabour S, Baer M, Deeb O, Leibscher M, Manz J, Xu X, Zilberg S. Molecular Symmetry Properties of Conical Intersections and Nonadiabatic Coupling Terms: Theory and Quantum Chemical Demonstration for Cyclopenta-2,4-dienimine (C5H4NH). J Phys Chem A 2009; 114:2991-3010. [DOI: 10.1021/jp905038t] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. Al-Jabour
- Institut für Chemie und Biochemie, Freie Universität Berlin, Germany, Faculty of Pharmacy, Al-Quds University, Palestine, The Fritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem, Israel, and Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University of Jerusalem, Israel
| | - M. Baer
- Institut für Chemie und Biochemie, Freie Universität Berlin, Germany, Faculty of Pharmacy, Al-Quds University, Palestine, The Fritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem, Israel, and Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University of Jerusalem, Israel
| | - O. Deeb
- Institut für Chemie und Biochemie, Freie Universität Berlin, Germany, Faculty of Pharmacy, Al-Quds University, Palestine, The Fritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem, Israel, and Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University of Jerusalem, Israel
| | - M. Leibscher
- Institut für Chemie und Biochemie, Freie Universität Berlin, Germany, Faculty of Pharmacy, Al-Quds University, Palestine, The Fritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem, Israel, and Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University of Jerusalem, Israel
| | - J. Manz
- Institut für Chemie und Biochemie, Freie Universität Berlin, Germany, Faculty of Pharmacy, Al-Quds University, Palestine, The Fritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem, Israel, and Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University of Jerusalem, Israel
| | - X. Xu
- Institut für Chemie und Biochemie, Freie Universität Berlin, Germany, Faculty of Pharmacy, Al-Quds University, Palestine, The Fritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem, Israel, and Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University of Jerusalem, Israel
| | - S. Zilberg
- Institut für Chemie und Biochemie, Freie Universität Berlin, Germany, Faculty of Pharmacy, Al-Quds University, Palestine, The Fritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem, Israel, and Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University of Jerusalem, Israel
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12
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Levi C, Halász GJ, Vibók A, Bar I, Zeiri Y, Kosloff R, Baer M. Intralines of quasi-conical intersections on torsion planes: methylamine as a case study. J Phys Chem A 2009; 113:6756-62. [PMID: 19462985 DOI: 10.1021/jp901072u] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recently we reported on a novel feature associated with the intersection of the two lowest states (1)A' and (1)A'' of the methylamine (J. Chem. Phys. 2008, 128, 244302). We established the existence of a finite (closed) line of conical intersections (ci), namely, a finite seam, located in the HC-NHH symmetry plane, a line that is formed by moving a single hydrogen on that plane while locking the positions of the (six) other atoms. In the present article, this study is extended to the corresponding torsion planes formed by rotating the methyl group around the CN axis. The torsion planes, in contrast with the HC-NHH symmetry plane, do not satisfy the symmetry feature that enables the seam just mentioned. Nevertheless, the calculated nonadiabatic coupling terms (NACTs) resemble features similar to those encountered in the HC-NHH symmetry plane. Following a tedious numerical study supported by a theoretical model (Section III), it was verified that these NACTs may become similar to those on the symmetry plane, sometimes even to the level of almost no distinction, but lack one basic feature; namely, they are not singular and therefore do not form topological effects.
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Affiliation(s)
- C Levi
- Department of Physics, Ben-Gurion University, Beer Sheva, 84105, Israel
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Levi C, Halász GJ, Vibók Á, Bar I, Zeiri Y, Kosloff R, Baer M. An intraline of conical intersections for methylamine. J Chem Phys 2008; 128:244302. [DOI: 10.1063/1.2943143] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Halász GJ, Vibók A, Suhai S, Baer M. The electronic nonadiabatic coupling term: Can it be ignored in dynamic calculations? J Chem Phys 2007; 127:244101. [DOI: 10.1063/1.2806167] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Halász GJ, Vibók Á, Baer M. Topological effects for nonsymmetrical configurations: The C2H2+ as a case study. J Chem Phys 2007; 127:144108. [DOI: 10.1063/1.2779035] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Sarkar B, Adhikari S, Baer M. Space-time contours to treat intense field-dressed molecular states. I. Theory. J Chem Phys 2007; 127:014301. [PMID: 17627340 DOI: 10.1063/1.2743437] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A molecular system exposed to an intense external field is considered. The strength of the field is measured by the number L of electronic states that become populated during this process. In the present article the authors discuss a rigorous way, based on the recently introduced space-time contours [R. Baer, et al., J. Chem. Phys. 119, 6998 (2003)], to form N coupled Schrodinger equations where N<L, which maintains the effects due to the remaining (L-N) populated states. It is shown that whereas the size of L is unlimited, the main requirement concerning N is that the original group of N field-free states forms a Hilbert subspace in the spatial region of interest. From previous studies it is known that a group of states forms a Hilbert subspace if and only if the corresponding topological D matrix is diagonal [M. Baer, et al., Farad, Discuss 127, 337 (2004)].
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Affiliation(s)
- Biplab Sarkar
- Department of Chemistry, Indian Institute of Technology, Guwahati, North Guwahati, Guwahati 781039, India
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Barragán P, Errea LF, Macías A, Méndez L, Rabadán I, Riera A. A study of conical intersections for the H3(+) system. J Chem Phys 2007; 124:184303. [PMID: 16709102 DOI: 10.1063/1.2193516] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A parametrization of the three asymptotic conical intersections between the energies of the H3(+) ground state and the first excited singlet state is presented. The influence of an additional, fourth conical intersection between the first and second excited states at the equilateral geometry on the connection between the three conical regions is studied, for both diatomics-in-molecules and ab initio molecular data.
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Affiliation(s)
- P Barragán
- Laboratorio Asociado al CIEMAT de Física Atómica y Molecular en Plasmas de Fusión, Departamento de Química, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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Halász GJ, Vibók A, Hoffman DK, Kouri DJ, Baer M. Renner-Teller/Jahn-Teller intersections along the collinear axes of polyatomic molecules: C2H2+ as a case study. J Chem Phys 2007; 126:154309. [PMID: 17461628 DOI: 10.1063/1.2717934] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recently we discussed the Renner-Teller effect in triatomic molecules [J. Chem. Phys. 125, 094102 (2006)]. In that article the main message is that the Renner-Teller phenomenon, just like the Jahn-Teller phenomenon, is a topological effect. Now we extend this study to a tetra-atomic system, namely, the C(2)H(2) (+) ion, for which topological effects are revealed when one atom surrounds the triatom axis or when two atoms surround (at a time) the two-atom axis. The present study not only supports the findings of the previous study, in particular, the crucial role played by the topological D matrix for diabatization, but it also reveals new features which are expected to be more and more pronounced the larger the original collinear molecule. As already implied, shifting away two atoms from the collinear molecular axis does not necessarily abolish the ability of the remaining two atoms to form topological effects. Moreover, the study indicates that when the two hydrogens are shifted away, the CC axis produces two kinds of topological effects: (1) a Renner-Teller effect (characterized by a topological phase of 2pi) which is revealed when the two hydrogens surround, rigidly, this axis (as mentioned above), and (2) a Jahn-Teller effect (characterized by a topological phase of pi) which is revealed when one of the hydrogens surrounds this axis while the other hydrogen is clamped to its position.
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Affiliation(s)
- G J Halász
- Department of Information Technology, University of Debrecen, P.O. Box 12, H-4010 Debrecen, Hungary
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Sarkar B, Adhikari S, Baer M. Do intense electromagnetic fields annihilate∕create conical intersections? J Chem Phys 2007; 126:014106. [PMID: 17212489 DOI: 10.1063/1.2423009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this article the authors relate the possibility that an intense electric field affects topological features of a molecular system. For this purpose they studied a model based on the Mathieu equation. They found that such a field may affect the spatial distribution of the nonadiabatic coupling terms but not the position of the intersections. In other words an intense electric field does not create or annihilate conical intersections. It is shown that this conclusion is valid as long as the field is an analytic function of the coordinates in the region of interest. These findings can be extended to magnetic fields (or electromagnetic fields) as long as they are analytic functions in the region of interest.
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Affiliation(s)
- Biplab Sarkar
- Department of Chemistry, Indian Institute of Technology-Guwahati, North Guwahati, Guwahati 781039, India
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Halász GJ, Vibók A, Baer R, Baer M. D matrix analysis of the Renner-Teller effect: An accurate three-state diabatization for NH2. J Chem Phys 2006; 125:094102. [PMID: 16965067 DOI: 10.1063/1.2336219] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Some time ago we published our first article on the Renner-Teller (RT) model to treat the electronic interaction for a triatomic molecule [J. Chem. Phys. 124, 081106 (2006)]. The main purpose of that Communication was to suggest considering the RT phenomenon as a topological effect, just like the Jahn-Teller phenomenon. However, whereas in the first publication we just summarized a few basic features to support that idea, here in the present article, we extend the topological approach and show that all the expected features that characterize a three (multi) state RT-type'3 system of a triatomic molecule can be studied and analyzed within the framework of that approach. This, among other things, enables us to employ the topological D matrix [Phys. Rev. A 62, 032506 (2000)] to determine, a priori, under what conditions a three-state system can be diabatized. The theoretical presentation is accompanied by a detailed numerical study as carried out for the HNH system. The D-matrix analysis shows that the two original electronic states 2A1 and 2B1 (evolving from the collinear degenerate Pi doublet), frequently used to study this Renner-Teller-type system, are insufficient for diabatization. This is true, in particular, for the stable ground-state configurations of the HNH molecule. However, by including just one additional electronic state--a B state (originating from a collinear Sigma state)--it is found that a rigorous, meaningful three-state diabatization can be carried out for large regions of configuration space, particularly for those, near the stable configuration of NH2. This opens the way for an accurate study of this important molecule even where the electronic angular momentum deviates significantly from an integer value.
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Affiliation(s)
- G J Halász
- Department of Information Technology, University of Debrecen, P.O. Box 12, H-4010 Debrecen, Hungary
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González-Lezana T, Roncero O, Honvault P, Launay JM, Bulut N, Aoiz FJ, Bañares L. A detailed quantum mechanical and quasiclassical trajectory study on the dynamics of the H++H2→H2+H+ exchange reaction. J Chem Phys 2006; 125:094314. [PMID: 16965087 DOI: 10.1063/1.2336224] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The H+ + H2 exchange reaction has been studied theoretically by means of a different variety of methods as an exact time independent quantum mechanical, approximate quantum wave packet, statistical quantum, and quasiclassical trajectory approaches. Total and state-to-state reaction probabilities in terms of the collision energy for different values of the total angular momentum obtained with these methods are compared. The dynamics of the reaction is extensively studied at the collision energy of E(coll)=0.44 eV. Integral and differential cross sections and opacity functions at this collision energy have been calculated. In particular, the fairly good description of the exact quantum results provided by the statistical quantum method suggests that the dynamics of the process is governed by an insertion mechanism with the formation of a long-lived collision complex.
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Affiliation(s)
- Tomás González-Lezana
- Instituto de Matemáticas y Física Fundamental (CSIC), Serrano 123, 28006 Madrid, Spain.
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Dhilip Kumar TJ, Saieswari A, Kumar S. Elastic and charge transfer processes in H+ + CO collisions. J Chem Phys 2006; 124:034314. [PMID: 16438590 DOI: 10.1063/1.2158998] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Proton and hydrogen atom time-of-flight spectra in collision energy range of E(trans) = 9.5-30 eV show that the endoergic charge transfer process in the H+ + CO system is almost an order of magnitude less probable than the elastic scattering [G. Niedner-Schatteburg and J. P. Toennies, Adv. Chem. Phys. LXXXII, 553 (1992)]. Ab initio computations at the multireference configuration interaction level have been performed to obtain the ground- and several low-lying excited electronic state potential energy curves in three different molecular orientations namely, H+ approaching the O-end and the C-end (collinear), and H+ approaching the CO molecule in perpendicular configuration with fixed CO internuclear distance. Nonadiabatic coupling terms between the ground electronic state (H+ + CO) and the three low-lying excited electronic states (H + CO+) have been computed and the corresponding diabatic potentials have been obtained. A time-dependent wavepacket dynamics study is modeled first involving only the ground and the first excited states and then involving the ground and the three lowest excited states at the collision energy of 9.5 eV. The overall charge transfer probability have been found to be approximately 20%-30% which is in qualitative agreement with the experimental findings.
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Affiliation(s)
- T J Dhilip Kumar
- Department of Chemistry, Indian Institute of Technology, Madras, Chennai 600 036, India
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Vértesi T, Bene E, Vibók A, Halász GJ, Baer M. N-State Adiabatic-to-Diabatic Transformation Angle: Theory and Application. J Phys Chem A 2005; 109:3476-84. [PMID: 16833685 DOI: 10.1021/jp044195z] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this article is discussed a new diabatization procedure which is expected to be reliable and, also, relatively easy to implement. This procedure takes into account the two main ingredients related to diabatization: (1) The size N of the smallest (relevant) group of states that forms a Hilbert subspace (this fact enforces the dimension of the adiabatic-to-diabatic transformation matrix to be N). (2) The total energy E which determines the number of open states, p, within this group of N states. The main emphasis in this manuscript is on the case that N is arbitrary but p is equal to 2. The various derivations as well as the final results are accompanied by numerical examples extracted from three- to five-state ab initio calculations for the H + H2 system.
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Affiliation(s)
- T Vértesi
- Department of Theoretical Physics, University of Debrecen, Debrecen, Hungary
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