화학공학소재연구정보센터
Journal of Physical Chemistry A, Vol.114, No.30, 7918-7927, 2010
Cavity Ring Down and Fourier Transform Infrared Spectroscopy at Low Temperatures (84-297 K): Fermi Resonance and Intensities of the C-H Fundamental and Overtone (Delta v=1-6) Transitions of CHD3
The C-H stretch fundamental and overtone absorptions of CHD3 have been obtained using Fourier transform infrared (FTIR), near-infrared, and phase shift and pulsed cavity ring down (CRD) techniques at temperatures between 84 and 297 K. The partially resolved rotational vibrational spectra of CHD3 that included the fundamental transition the overtone transitions, and combination bands 5v(1) and 4v(1) + 2v(5) and 6v(1) and 5v(1) + 2v(5) were obtained and compared with the simulated spectra at the corresponding temperature. The strength of the Fermi resonance between levels vv(1) and (v - 1)v(1) + 2v(5) with v = 2-6 was calculated using the experimental perturbed energies and relative peak intensities. The integrated absorption was calculated as a function of the density of the gas samples and used to obtain the cross section and the band strength of the Delta v = 5 and 6 transitions. Ab initio molecular orbital calculations were clone to obtain the dipole moment function (DMF) as a function of the C-H internuclear distance. Intensity calculations with the DMF correctly predict the order of magnitude of the experimental band strengths.