Local mode overtone intensities of SiH4 and GeH4 from a bond dipole model with an ab initio calculated dipole moment surface

The absorption intensities of the local mode overtones of SiH4 and GeH4 were investigated by a bond dipole model with ab initio calculated dipole moment surfaces, which were obtained by using the density functional method B3PW91 with a 6-311++G(3df, 2pd) basis set and then fitted to the Mecke type function. The calculated overtone intensities agree with the observed values.