Hi all, i am studying the physics of Raman Spectra. Was able to understand the origin of Vibrational Raman Spectra... which was an effect due to the change of polarizability with internuclear distance due to molecular vibration. But, i still yet to figure out why rotation of molecules can result in Raman spectra too? i'm reading the book 'molecular physics and elements of quantum chemistry' by H. Haken. They mention something about the polarizability of the molecule as a tensor and that its their tensor anisotropy that contribute to this effect. But i was not able to appreciate in essence why this is so... Can someone pls direct me to better resource on this? Thanks.