THE INTERPRETATION OF THE C(1)PI[-A(1)DELTA EXCITATION-SPECTRA OF THEARNH COMPLEX

We use slightly modified versions of earlier ab initio potential energ y surfaces for Ar+NH(a (1) Delta) and Ar+NH(c (II)-I-1) to investigate the bend-stretch levels of ArNH complexes, both within an adiabatic b ender model and in full variational calculations. The positions of the se levels are used to reinterpret the fluorescence excitation spectra reported previously [R. W. Randall, C.-C. Chuang, and M. I. Lester, Ch em. Phys. Lett. 200, 113 (1992)]. The first 15 observed bands can be u nambiguously assigned, with near-quantitative accuracy. The weak aniso tropy in the lower electronic state [ArNH(a (1) Delta)] complicates th e rotational structure, since each band involves overlapped transition s out of several, nearly degenerate bend-stretch levels of the complex . (C) 1995 American Institute of Physics.