The comparison of temporal bond polarizabilities of the nonresonant Raman excited virtual state of ethylene thiourea by two different algorithms

Abstract

We studied the temporal bond polarizabilities of ethylene thiourea (ETU) from the Raman intensities by two different algorithms. One algorithm includes only the bond stretching modes and the other includes all bond modes. Our analysis shows that, the algorithm using bond stretching modes, in which only the part of Raman peaks whose vibrational modes have relatively larger proportion in the bond stretching are considered, may have larger errors in certain situations where the stretching and bending modes have significant coupling. Otherwise, this algorithm is just suitable, although it may lose certain physical information. The bond polarizabilities provide much information concerning the electronic distribution of nonresonant Raman excited virtual state. At the initial moment of the 514.5 nm excitation, the tendency of the excited electrons is to spread to the molecular periphery. Meanwhile, the relaxation process of the bond polarizability and the characteristic times for these two models are almost the same.