A method using the symmetry properties of molecules has been developed
for describing high resolution Raman spectra. This method can be appl
ied to spontaneous Raman scattering and to nonlinear Raman scattering
or resonance Raman spectroscopy. A high sensitivity laser Raman spectr
ometer has been constructed and some weak vibration rotation bands of
diatomic molecules have been observed. The polarizability functions of
N-2 and O-2 are determined. The laser spectrometer has been used for
gas diagnostics.