Absorption and Emission Spectra of OH and OD in Solid Ne. Evidence for Rotation

Abstract

The ${\mathrm{A\hspace{0.17em}}}^3{\displaystyle \sum }{\hspace{0.17em}}^{+}{\mathrm{\hspace{0.17em}-X\hspace{0.17em}}}^2{{\displaystyle \prod }}_i$ system of OH and OD has been studied in solid Ne at 4.2°K. Both absorption and emission spectra have been recorded, the latter for the first time for OH or OD in a solid matrix. Emission is seen from $\text{υ′\hspace{0.17em}>\hspace{0.17em}0,}$ establishing a relatively slow vibrational relaxation rate in the ${\mathrm{A\hspace{0.17em}}}^3{{\displaystyle \sum }}^{+}$ state for OH and OD in solid Ne. Considerable fine structure is seen, which differs for the two isotopes and is not a mirror image in absorption and emission. This structure bears no resemblance to the structure previously observed for OH and OD in the other rare gases. The observed structure in solid Ne can be partly interpreted in terms of slightly perturbed rotational motion in the solid. The larger perturbation for OH compared with OD suggests that translation‐rotation coupling may be important. Rotational relaxation times shorter than 10⁻⁶ sec have been established from the lack of rotational “hot‐band” structure in the emission spectrum.