Charge disturbance/excitation in the Raman virtual state revealed by ROA signal: A case study of pinane

The Raman mode intensities are used to extract the bond polarizabilities which are the indication of the charge disturbance/excitation of the Raman virtual state. A classical formula based on the electric and magnetic dipolar coupling among the charges on the atoms is developed which relates the charges and vibrational amplitudes of the atoms in a normal mode to the Raman optical activity(ROA) mode signatures. By fitting with the experimental ROA signatures, we are able to elucidate the scaling parameter which relates the bond polarizability to the electric charge. The result shows that around40% of the charges in pinane are involved in the Raman process under 532 nm laser excitation.