Electronic spectroscopy and dynamics of the CH/D–Ne Van der Waals complex

Abstract

Rotationally resolved spectra for the Bx ²σ^––X ²Π transition of CH/D–Ne have been recorded. Bands of the complex were observed in association with the monomer 0–0 and 1–0 transitions. Analyses of the rovibronic structure show that the complex is weakly bound in both the X and B states. Excitation to the B state weakens and lengthens the intermolecular bond. Hindered internal rotation (HIR) was observed in the B state, which has a linear equilibrium geometry. Rotational predissociation was evident in spectra for the n= 2 HIR levels of CH/D–Ne, and the n= 1, K= 0 level of CH–Ne.

The rotational levels of CH/D(X)–Ne were characterized by half-integer quantum numbers. In contrast, the rotational levels of CH/D(X)–Ar are known to be consisten with integer quantum numbers (G. W. Lemire, M. J. McQuaid, A. J. Kotlar and R. C. Sausa, J. Chem. Phys., 1993, 99, 91). Models of the angular momentum coupling in CH(X)–Rg complexes have been used to examine possible causes for this qualitative difference.