Optical and Neutron Inelastic Scattering Study of 2,3-Dimethylnorbornanes

Article abstract of DOI:10.1021/j100401a008

We have measured the infrared, Raman, and neutron vibrational spectra of the 2,3-dimethylnorbornanes with two CH3 or CD3 groups in the 2- and 3-exo or endo positions.A normal-coordinate analysis has been carried out.No coupling reflecting the strain due to the methyl group appears in the C-CH3 bending and torsional modes of the trans isomer, but appears in the cis-exo isomer (average value 23 cm^-1) and in the cis-endo isomer (average value 28 cm^-1.The frequencies are used for the determination of the thermodynamic contribution to the standard free energy differences.