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Boussessi R, Senent ML. Computational analysis of the far infrared spectral region of various deuterated varieties of ethylene glycol. Phys Chem Chem Phys 2020; 22:23785-23794. [PMID: 33063802 DOI: 10.1039/d0cp03315d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The far infrared spectra of three deuterated isotopologues of ethylene glycol, CH2OD-CH2OD, CH2OD-CH2OH and CH2OH-CH2OD, where the latter two species differ in their intramolecular hydrogen-bonding arrangement, are studied using highly correlated ab initio methods, vibrational second order perturbation theory and a variational procedure of reduced dimensionality. New subroutines suitable for the study of large systems with more than two interacting large amplitude motions were implemented and applied. The molecular symmetry of ethylene glycol decays by the formation of weak intramolecular bonds producing very asymmetrical stable structures. Three internal rotations contribute to the formation of a very anisotropic potential energy surface and to the puzzling distribution of the rovibrational energy levels. The ground vibrational state rotational constants and the centrifugal distortion constants (S-reduction, Ir representation) corresponding to the aGg' (G1) and gGg' (G2) forms are provided for the studied isotopologues. The low-lying vibrational levels up to 550 cm-1 are obtained variationally for J = 0. Two series of sublevels of the ground vibrational state are obtained: eight components localized in G1 lying between 0.0 and 0.3 cm-1 and eight sublevels localized in G2 lying between 138.1 and 138.4 cm-1. The gap between both sets is lower in CH2OD-CH2OD and more dispersed in the monodeuterated variety.
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Affiliation(s)
- Rahma Boussessi
- Departamento de Química y Física Teóricas, Instituto de Estructura de la Materia, IEM-CSIC, Unidad Asociada GIFMAN, CSIC-UHU, Serrano 121, Madrid 28006, Spain.
| | - María Luisa Senent
- Departamento de Química y Física Teóricas, Instituto de Estructura de la Materia, IEM-CSIC, Unidad Asociada GIFMAN, CSIC-UHU, Serrano 121, Madrid 28006, Spain.
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Hudson RL, Coleman FM. Infrared intensities and molar refraction of amorphous dimethyl carbonate – comparisons to four interstellar molecules. Phys Chem Chem Phys 2019; 21:11284-11289. [DOI: 10.1039/c9cp01709g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first measurements of infrared (IR) band intensities of solid dimethyl carbonate are presented along with measurements of this compound's refractive index and density near 15 K, neither of which has been reported.
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Affiliation(s)
- Reggie L. Hudson
- Astrochemistry Laboratory
- NASA Goddard Space Flight Center
- Greenbelt
- USA
| | - Falvia M. Coleman
- Astrochemistry Laboratory
- NASA Goddard Space Flight Center
- Greenbelt
- USA
- InuTeq
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Adsorption Characteristics of Bixin on Acid- and Alkali-Treated Kaolinite in Aprotic Solvents. Bioinorg Chem Appl 2018; 2018:3805654. [PMID: 29581720 PMCID: PMC5822873 DOI: 10.1155/2018/3805654] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 10/31/2017] [Indexed: 11/23/2022] Open
Abstract
The adsorption of bixin in aprotic solvents onto acid- and alkali-treated kaolinite was investigated. Kaolinite was treated three times, for 6 h each, with 8 M HCl or 5 M KOH. The adsorbents were characterized by XRD, FT-IR, EDS, and BET-N2. The effects of contact time and dye concentration on adsorption capacity and kinetics, electronic transition of bixin before and after adsorption, and also mechanism of bixin-kaolinite adsorption were investigated. Dye adsorption followed pseudo-second order kinetics and was faster in acetone than in dimethyl carbonate. The best adsorption results were obtained for KOH-treated kaolinite. In both of the solvents, the adsorption isotherm followed the Langmuir model and adsorption capacity was higher in dimethyl carbonate (qm = 0.43 mg/g) than in acetone (0.29 mg/g). The adsorption capacity and kinetics of KOH-treated kaolinite (qm = 0.43 mg/g, k2 = 3.27 g/mg·min) were better than those of HCl-treated kaolinite (qm = 0.21 mg/g, k2 = 0.25 g/mg·min) and natural kaolinite (qm = 0.18 mg/g, k2 = 0.32 g/mg·min). There are shift in the band position of maximum intensity of bixin after adsorption on this adsorbent. Adsorption in this system seemed to be based essentially on chemisorption due to the electrostatic interaction of bixin with the strong basic and reducing sites of kaolinite.
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Dalbouha S, Senent ML, Komiha N, Domínguez-Gómez R. Structural and spectroscopic characterization of methyl isocyanate, methyl cyanate, methyl fulminate, and acetonitrile N-oxide using highly correlated ab initio methods. J Chem Phys 2017; 145:124309. [PMID: 27782665 DOI: 10.1063/1.4963186] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Various astrophysical relevant molecules obeying the empirical formula C2H3NO are characterized using explicitly correlated coupled cluster methods (CCSD(T)-F12). Rotational and rovibrational parameters are provided for four isomers: methyl isocyanate (CH3NCO), methyl cyanate (CH3OCN), methyl fulminate (CH3ONC), and acetonitrile N-oxide (CH3CNO). A CH3CON transition state is inspected. A variational procedure is employed to explore the far infrared region because some species present non-rigidity. Second order perturbation theory is used for the determination of anharmonic frequencies, rovibrational constants, and to predict Fermi resonances. Three species, methyl cyanate, methyl fulminate, and CH3CON, show a unique methyl torsion hindered by energy barriers. In methyl isocyanate, the methyl group barrier is so low that the internal top can be considered a free rotor. On the other hand, acetonitrile N-oxide presents a linear skeleton, C3v symmetry, and free internal rotation. Its equilibrium geometry depends strongly on electron correlation. The remaining isomers present a bend skeleton. Divergences between theoretical rotational constants and previous parameters fitted from observed lines for methyl isocyanate are discussed on the basis of the relevant rovibrational interaction and the quasi-linearity of the molecular skeleton.
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Affiliation(s)
- S Dalbouha
- Departamento de Química y Física Teóricas, Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, Madrid 28006, Spain
| | - M L Senent
- Departamento de Química y Física Teóricas, Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, Madrid 28006, Spain
| | - N Komiha
- LS3ME-Equipe de chimie théorique et Modélisation, Faculté des Sciences Rabat-Université Mohammed V, 4 Avenue Ibn Battouta B.P. 1014 RP, Rabat, Morocco
| | - R Domínguez-Gómez
- E.T.S. de Ingeniería Civil, Universidad Politécnica de Madrid, Alfonso XII, 3-5, Madrid 28014, Spain
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Wu X, Zhou X, Hemberger P, Bodi A. Dissociative Photoionization of Dimethyl Carbonate: The More It Is Cut, the Bigger the Fragment Ion. J Phys Chem A 2017; 121:2748-2759. [DOI: 10.1021/acs.jpca.7b00544] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiangkun Wu
- Hefei
National Laboratory for Physical Sciences at the Microscale and Department
of Chemical Physics, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Xiaoguo Zhou
- Hefei
National Laboratory for Physical Sciences at the Microscale and Department
of Chemical Physics, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Patrick Hemberger
- Laboratory
for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Andras Bodi
- Laboratory
for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute, 5232 Villigen, Switzerland
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Boussessi R, Senent ML, Jaïdane N. Weak intramolecular interaction effects on the torsional spectra of ethylene glycol, an astrophysical species. J Chem Phys 2017; 144:164110. [PMID: 27131534 DOI: 10.1063/1.4947088] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
An elaborate variational procedure of reduced dimensionality based on explicitly correlated coupled clusters calculations is applied to understand the far infrared spectrum of ethylene-glycol, an astrophysical species. This molecule can be classified in the double molecular symmetry group G8 and displays nine stable conformers, gauche and trans. In the gauche region, the effect of the potential energy surface anisotropy due to the formation of intramolecular hydrogen bonds is relevant. For the primary conformer, stabilized by a hydrogen bond, the ground vibrational state rotational constants are computed to be A0 = 15 369.57 MHz, B0 = 5579.87 MHz, and C0 = 4610.02 MHz corresponding to differences of 6.3 MHz, 7.2 MHz, and 3.5 MHz from the experimental parameters. Ethylene glycol displays very low torsional energy levels whose classification is not straightforward and requires a detailed analysis of the torsional wavefunctions. Tunneling splittings are significant and unpredictable due to the anisotropy of the potential energy surface PES. The ground vibrational state splits into 16 sublevels separated ∼142 cm(-1). The splitting of the "G1 sublevels" was calculated to be ∼0.26 cm(-1) in very good agreement with the experimental data (0.2 cm(-1) = 6.95 MHz). Transitions corresponding to the three internal rotation modes allow assignment of previously observed Q branches. Band patterns, calculated between 362.3 cm(-1) and 375.2 cm(-1), 504 cm(-1) and 517 cm(-1), and 223.3 cm(-1) and 224.1 cm(-1), that correspond to the tunnelling components of the v21 fundamental (v21 = OH-torsional mode), are assigned to the prominent experimental Q branches.
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Affiliation(s)
- R Boussessi
- Departamento de Química y Física Teóricas, I. Estructura de la Materia, IEM-CSIC, Serrano 121, Madrid 28006, Spain
| | - M L Senent
- Departamento de Química y Física Teóricas, I. Estructura de la Materia, IEM-CSIC, Serrano 121, Madrid 28006, Spain
| | - N Jaïdane
- Laboratoire de Spectroscopie Atomique, Moléculaire et Applications-LSAMA LR01ES09, Faculté des sciences de Tunis, Université de Tunis El Manar, 2092 Tunis, Tunisia
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Alcalde R, Atilhan M, Trenzado JL, Aparicio S. Physicochemical Insights on Alkylcarbonate–Alkanol Solutions. J Phys Chem B 2016; 120:5015-28. [DOI: 10.1021/acs.jpcb.6b02961] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rafael Alcalde
- Department
of Chemistry, University of Burgos, 09001 Burgos, Spain
| | - Mert Atilhan
- Department
of Chemical Engineering, Qatar University, P.O. Box 2713, Doha, Qatar
| | - José Luis Trenzado
- Departamento
de Física, Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas G.C., Spain
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