Ab initio analysis of Raman trace scattering intensities in alkenes and silanes

Molecular polarizabilities and derivatives with respect to CC, CH, SiSi and SIH stretching modes were obtained from ab initio molecular orbital calculations at the HF/6-311G (3df,3pd) level for 14 molecules: ethene, cyclopropene, cyclobutadiene, cyclopentadiene, cis- and trans-butadiene, transhexatriene, benzene, naphthalene and the silanes Sit to Si5. Factors governing the trends in the intensities include conformation, chain length, location and orientation of a bond within the molecular framework. The results are compared with those from earlier studies on saturated alkanes and other work on conducting polymers. Copyright (C) 2002 John Wiley Sons, Ltd.