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Knaanie R, Šebek J, Tsuge M, Myllys N, Khriachtchev L, Räsänen M, Albee B, Potma EO, Gerber RB. Infrared Spectrum of Toluene: Comparison of Anharmonic Isolated-Molecule Calculations and Experiments in Liquid Phase and in a Ne Matrix. J Phys Chem A 2016; 120:3380-9. [DOI: 10.1021/acs.jpca.6b01604] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Roie Knaanie
- Institute
of Chemistry and The Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel
| | - Jiří Šebek
- Institute
of Chemistry and The Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel
- Department
of Physical Chemistry, University of Chemistry and Technology, Prague 16628, Czech Republic
| | - Masashi Tsuge
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Nanna Myllys
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Leonid Khriachtchev
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Markku Räsänen
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Brian Albee
- Department
of Chemistry, University of California, Irvine, California 92697, United States
| | - Eric O. Potma
- Department
of Chemistry, University of California, Irvine, California 92697, United States
| | - R. Benny Gerber
- Institute
of Chemistry and The Fritz Haber Research Center, The Hebrew University, Jerusalem 91904, Israel
- Department
of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
- Department
of Chemistry, University of California, Irvine, California 92697, United States
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Govindarajan M, Periandy S, Carthigayen K. FT-IR and FT-Raman spectra, thermo dynamical behavior, HOMO and LUMO, UV, NLO properties, computed frequency estimation analysis and electronic structure calculations on α-bromotoluene. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 97:411-422. [PMID: 22820044 DOI: 10.1016/j.saa.2012.06.028] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 05/04/2012] [Accepted: 06/10/2012] [Indexed: 06/01/2023]
Abstract
In this work, the vibrational spectral analysis was carried out by using Raman and infrared spectroscopy in the range 100-4,000 cm(-1) and 50-4,000 cm(-1), respectively, for the title molecules. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on Hartee Fock (HF) and density functional theory (DFT) method and different basis sets combination. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The scaled B3LYP/6-311++G(d,p) results show the best agreement with the experimental values over the other methods. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The influences of bromine atom and methyl group on the geometry of benzene and its normal modes of vibrations have also been discussed. The results of the calculations were applied to simulated spectra of the title compounds, which show excellent agreement with observed spectra.
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Affiliation(s)
- M Govindarajan
- Department of Physics, MGGA College, Mahe, U.T. Puducherry, India.
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Govindarajan M, Karabacak M. Analysis of vibrational spectra (FT-IR and FT-Raman) and nonlinear optical properties of organic 2-chloro-p-xylene. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 94:36-47. [PMID: 22510490 DOI: 10.1016/j.saa.2012.03.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 03/06/2012] [Accepted: 03/10/2012] [Indexed: 05/31/2023]
Abstract
In this work, the vibrational spectral analysis was carried out by using FT-Raman and FT-IR spectroscopy in the range 100-4000cm(-1) and 400-4000cm(-1) respectively, for the title molecule. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on Hartree-Fock (HF) and density functional theory (DFT) method with 6-311++G(d,p) basis set. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The scaled B3LYP/6-311++G(d,p) results show the best agreement with the experimental values over the other method. The influences due to the substitution of halogen bond and methyl group were investigated. The results of the calculations are applied to simulate the vibrational spectra of the title compound, which show excellent agreement with observed spectra. The absorption energy and oscillator strength are calculated by time-dependent density functional theory (TD-DFT). Besides, frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP), and thermodynamic properties were performed. Mulliken charges of the title molecule were also calculated and interpreted. The dipole moment, linear polarizability and first hyperpolarizability values were also computed.
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Govindarajan M, Karabacak M, Periandy S, Xavier S. Vibrational spectroscopic studies, NLO, HOMO-LUMO and electronic structure calculations of α,α,α-trichlorotoluene using HF and DFT. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 94:53-64. [PMID: 22516115 DOI: 10.1016/j.saa.2012.03.074] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Revised: 03/12/2012] [Accepted: 03/21/2012] [Indexed: 05/31/2023]
Abstract
FT-IR and FT-Raman spectra of α,α,α-trichlorotoluene have been recorded and analyzed. The geometry, fundamental vibrational frequencies are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) B3LYP/6-311++G(d,p) method and a comparative study between HF level and various basis sets combination. The fundamental vibrational wavenumbers as well as their intensities were calculated and a good agreement between observed and scaled calculated wavenumbers has been achieved. The complete vibrational assignments of wavenumbers are made on the basis of potential energy distribution (PED). The effects due to the substitutions of methyl group and halogen were investigated. The absorption energy and oscillator strength are calculated by time-dependent density functional theory (TD-DFT). The electric dipole moment, polarizability and the first hyperpolarizability values of the α,α,α-trichlorotoluene have been calculated. (1)H NMR chemical shifts were calculated by using the gauge independent atomic orbital (GIAO) method with HF and B3LYP methods with 6-311++G(d,p) basis set. Moreover, molecular electrostatic potential (MEP) and thermodynamic properties were performed. Mulliken and natural charges of the title molecule were also calculated and interpreted.
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Govindarajan M, Karabacak M, Suvitha A, Periandy S. FT-IR, FT-Raman, ab initio, HF and DFT studies, NBO, HOMO-LUMO and electronic structure calculations on 4-chloro-3-nitrotoluene. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 89:137-148. [PMID: 22261102 DOI: 10.1016/j.saa.2011.12.067] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 12/19/2011] [Accepted: 12/21/2011] [Indexed: 05/31/2023]
Abstract
In this work, the vibrational spectral analysis was carried out by using Raman and infrared spectroscopy in the range 100-4000 cm(-1) and 50-4000 cm(-1), respectively, for 4-chloro-3-nitrotoluene (C7H6NO2Cl) molecule. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on Hartree Fock (HF) and density functional theory (DFT) method and different basis sets combination. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The scaled B3LYP/6-311++G(d,p) results show the best agreement with the experimental values over the other methods. The calculated HOMO and LUMO energies shows that charge transfer within the molecule. The effects due to the substitutions of methyl group, nitro group and halogen were investigated. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Besides, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) and thermodynamic properties were performed.
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Tokatlı A, Ozen E, Ucun F, Bahçeli S. Quantum chemical computational studies on 5-(4-bromophenylamino)-2-methylsulfanylmethyl-2H-1,2,3-triazol-4-carboxylic acid ethyl ester. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 78:1201-1211. [PMID: 21247796 DOI: 10.1016/j.saa.2010.12.083] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 12/07/2010] [Accepted: 12/31/2010] [Indexed: 05/30/2023]
Abstract
The optimized molecular geometry, vibrational frequencies, and gauge including atomic orbital (GIAO) (1)H and (13)C NMR shift values of 5-(4-bromophenylamino)-2-methylsulfanylmethyl-2H-1,2,3-triazol-4-carboxylic acid ethyl ester have been calculated by using Hartree-Fock (HF) and density functional method (DFT/B3LYP) with 6-31G(d), 6-31G(d,p) and LANL2DZ basis sets. The optimized molecular geometric parameters were presented and compared with the data obtained from X-ray diffraction. In order to fit the calculated harmonic wavenumbers to the experimentally observed ones, scaled quantum mechanics force field (SQM FF) methodology was proceeded. Correlation factors between the experimental and calculated (1)H chemical shift values of the title compound in vacuum and in CHCl(3) solution by using the conductor-like screening continuum solvation model (COSMO) were reported. The calculated results showed that the optimized geometry well reproduces the crystal structure. The theoretical vibrational frequencies and chemical shifts are in very good agreement with the experimental data. In solvent media the energetic behavior of the title compound was also examined by using the B3LYP method with the 6-31G(d) basis set, applying the COSMO model. The obtained results indicated that the total energy of the title compound decreases with increasing polarity of the solvent. Furthermore, molecular electrostatic potential (MEP), natural bond orbital (NBO) and frontier molecular orbitals (FMOs) of the title compound were performed by the B3LYP/LANL2DZ method, and also thermodynamic parameters for the title compound were calculated at all the HF and B3LYP levels.
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Affiliation(s)
- Ahmet Tokatlı
- Department of Physics, Faculty of Art and Science, Süleyman Demirel University, Isparta, Turkey.
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Govindarajan M, Ganasan K, Periandy S, Karabacak M, Mohan S. Vibrational spectroscopic analysis of 2-chlorotoluene and 2-bromotoluene: a combined experimental and theoretical study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 77:1005-1013. [PMID: 20869295 DOI: 10.1016/j.saa.2010.08.038] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 08/14/2010] [Accepted: 08/24/2010] [Indexed: 05/29/2023]
Abstract
In this work, the vibrational spectral analysis was carried out using Raman and infrared spectroscopy in the range 100-4000 cm(-1) and 50-4000 cm(-1), respectively, for the title molecules. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on Hartee Fock (HF) and density functional theory (DFT) method and different basis sets combination. The complete vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED). The scaled B3LYP/6-311++G(d,p) results show the best agreement with the experimental values over the other methods. The effects due to the substitutions of methyl group and halogen bond were investigated. The results of the calculations were applied to simulated spectra of the title compounds, which show excellent agreement with observed spectra.
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Affiliation(s)
- M Govindarajan
- Department of Physics, Avvaiyar Govt. College Women, 46/1, Sivan Koil Street, Poovam, Kottucherry, Karaikal, Puducherry 609 609, India.
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Baker J, Wolinski K. Isomerization of stilbene using enforced geometry optimization. J Comput Chem 2010; 32:43-53. [DOI: 10.1002/jcc.21597] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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