Optical Radio-Frequency Double Resonance in Molecules: The OH Radical

Abstract

The $g$ values for the two hyperfine components of the $J^{\prime }=\frac{3}{2}$, $K^{\prime }=2\mathrm{}$, $v^{\prime }=0\mathrm{}$ level of the $A{}_{}{}^2{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}$ state of OH have been determined using the technique of optical radio-frequency double resonance. They are found to be $g(F=2\mathrm{})=0.301\mathrm{}\pm 0.0015$ and $g(F=1\mathrm{})=0.492\mathrm{}\pm 0.0045$ in agreement with the values calculated assuming Hund's case (b) coupling. From our earlier measurement of $g\tau$ for this state, the radiative lifetime is found to be (7.7±0.8) × ${10}^{-7\mathrm{}}$ sec, corresponding to a band oscillator strength $f_{00}=(9.3\mathrm{}\pm 1.0)\times {10}^{-4\mathrm{}}$.