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Ab initio simulation of benzene Raman intensities
Author(s) -
Ozkabak Ali G.,
Thakur Surya N.,
Goodman Lionel
Publication year - 1991
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560390317
Subject(s) - chemistry , basis set , polarizability , ab initio , fermi resonance , atomic physics , raman scattering , molecular physics , scattering , ab initio quantum chemistry methods , normal mode , resonance (particle physics) , raman spectroscopy , harmonic , molecule , computational chemistry , physics , density functional theory , quantum mechanics , vibration , organic chemistry
C 6 H 6 Raman scattering activities calculated from harmonic model ab initio Hartree–Fock 6–311 ++ G( d , p ) polarizability derivatives (and harmonic force fields calculated at the same level) accurately simulate experiment (to within 1% for the a 1 g modes). Accurate predictions are also made for the e 2 g modes (to within 5% for ν 7 and ν 9 , and more poorly for ν 6 and ν 8 [in Fermi resonance with ν 6 + ν 1 ]) and for the e 1 g out‐of‐plane mode, ν 10 . Only the ν 6 in‐plane CCC bending mode scattering activity is found to be anomalous. Systematic variation of the basis set indicates that the benzene scattering activities and depolarization ratios are strongly dependent on inclusion of both carbon and hydrogen atom diffuse functions in the basis set. Predictions are also made for 12 C 6 D 6 and for unmeasured intensities in 13 C 6 H 6 . Measurements of a 1 g mode scattering activities in the latter molecule are predicted to be useful in testing the harmonic Hartree–Fock Raman intensity model.