Raman intensities using time dependent density functional theory

The Raman activities of a variety of small molecules, H2O, H2S, CO2, NH3, H2CO, CH3OH, CH4, C2H2, C2H4 and C2H6, are calculated using time dependent density functional theory. The geometric derivatives of the static polarisability are obtained using self-consistent field (SCF), second order Møller–Plesset theory and DFT, the latter using a local density approximation, a gradient corrected functional, PBE, and the hybrid functionals, B3LYP, PBE0, and B97. Derivatives of the dynamic polarisability are obtained using both SCF and the same density functionals as were used for the static case. It is found that the effects of electron correlation are significant, as is the frequency dependence.