HIGH RESOLUTION STIMULATED RAMAN SPECTROSCOPY OF $0_{2}^{\ast}$

Abstract

High resolution $(0.002 cm^{-1})$ stimulated Raman $spectra^{1}$ of the fundamental vibrational band of $0_{2}$ have been recorded at room temperature and, using a pulsed free-expansion $jet^{2}$, at 50k. These spectra include the normal Q-branch and the satellite Q-branches at $1554 cm^{-1}$ and $1558 cm^{-1}$ that arise due to the splitting of the $^{3}\Sigma_{g}$ ground state of molecular oxygen by spin-spin and spin-rotation interactions. Both satellite Q-branches were completely resolved for the first time. Measured intensity ratios for the ${\Delta N}\Delta J(J.N) = ^{Q} 0(2,1)$ and $^{Q} R(1,1)$ lines, and for the $^{Q} S(0,1)$ and $^{Q} P(2,1)$ lines compare favorably with that for a coupling case intermediate between Hund's Cases (a) and (b). Depolarization ratios, measured for a series of $Q^{Q}$-branch (unresolved) triplets. give a value $0.164 \pm 0.004$ for the depolarization ratio of the fundamental vibrational band.