Vibration-rotation polarizability operator for nonlinear X_2Y-type molecules and the rovibrational Raman cross-section calculation of water molecules

摘要

The expression for the second - order transformed polarizability operator for non-linear X_2Y -type molecules is derived using the method of contact transformation. This operator is used for the calculation of ro-vibrational Raman cross sections of the H_2O molecule. It is shown that the ro-vibrational correction terms change the integral intensity of pure rotational lines significantly and the ν_2 band slightly. The vibrational dependence of the mean polarizability of H_2O is analyzed in the calculation of integral intensity of one and two quantum bands.