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Theoretical and experimental studies for the interpretation of vibrational circular dichroism spectra in the CH‐stretching overtone region
Author(s) -
Abbate Sergio,
Longhi Giovanna,
Santina Claudio
Publication year - 2000
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/(sici)1520-636x(2000)12:4<180::aid-chir4>3.0.co;2-2
Subject(s) - chemistry , anharmonicity , vibrational circular dichroism , hamiltonian (control theory) , overtone , spectral line , molecular physics , fourier transform , amplitude , infrared spectroscopy , computational chemistry , harmonic , circular dichroism , quantum mechanics , crystallography , physics , mathematical optimization , mathematics , organic chemistry
Two theoretical models for the interpretation of the existing data of CH‐stretching overtones' vibrational circular dichroism data are presented. The first model is based on the quantum mechanical Van Vleck contact transformation theory and is applied to the full vibrational problem, the second is based on classical trajectories calculations, by which we treat a simplified three‐degrees of freedom Hamiltonian. The latter allows one to derive a qualitative but efficacious picture of the behavior of coupled anharmonic oscillators. In this framework, we analyze the Poincaré Surfaces of Section, and calculate the Fourier Cross Spectra of coupled CH‐stretchings. Values for the harmonic frequencies and anharmonicities are derived from absorption spectra in the near infrared on partially deuterated compounds. The effect of large amplitude, low‐frequency puckering or twisting modes on the ensemble of coupled CH‐stretching is taken into account. Chirality 12:180–190, 2000. © 2000 Wiley‐Liss, Inc.