Measurement and calculation of the Raman optical activity of alpha-pinene and trans-pinane

Raman scattering and Raman optical activity (ROA) spectra of alpha-pinene and trans-pinane were measured for both enantiomers. The experiment was performed on a newly built, fully computer-controlled backscattering incident circular polarization ROA instrument. High-quality spectra were obtained and interpreted on the basis of ab initio quantum chemical calculations. Excellent agreement between the calculated and observed spectra was observed in the mid IR region. An approximate distributed origin gauge model for calculation of the polarization tensors was proposed. The shapes of ROA spectra calculated with this model are similar to those obtained with conventional, computationally more demanding ROA computations.