Zero-field level crossing and optical radio-frequency double resonance studies of the <i>A</i> 2Σ+ states of OH and OD

Abstract

We have performed Hanle effect and double resonance measurements on the ν′= 0, N′= 2, J′= 3/2 level of the OH A 2Σ+ state and on the ν′= 0, N′= 1, J′= 3/2 level of the OD A 2Σ+ state using atomic line excitation. The double resonance signal is followed as a function of static magnetic field. For OH the Zeeman splitting is found to be linear up to the highest fields investigated whereas in OD the deviations from linearity yield a value for the combination of hyperfine constants b+c/5= 121± 14 MHz. In the case of OH, both the F′ = 1 and F′ = 2 hyperfine components contribute to the Hanle signal; in the case of OD, the Hanle signal arises almost entirely from the F′ = 5/2 component. In the former case, measurement of the relative intensities of the F′ = 1 and F′ = 2 double resonance signals gives the relative populations of these components. From the linewidths of the zero-field level crossings, along with the analysis of the optical double resonance data, the radiative lifetimes for the above (ν′,N′,J′) levels of the A 2Σ+ states of OH and OD are determined to be 0.58±0.05 and 0.65±0.05 μsec, respectively.