		15min:

ANALYSIS OF PERTURBATIONS OBSERVED IN THE FT SPECTRA OF CuCl₂.

A. YIANNOPOULOU, A. J. ROSS, P. CROZET, Laboratoire de Spectrométrie Ionique et Moléculaire, CNRS et Université Lyon-I (UMR 5579), Campus la Doua, 69622 Villeurbanne Cedex, France; AND J. M. BROWN, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, England.

Abnormally large e-f separations have been observed in the (v₁, 0, v₃) levels of the ground X²_g(3/2) state of CuCl₂ about 2500 cm^-1 above the lowest vibrational level (0,0,0). The largest splittings are accompanied by extra lines in the dispersed fluorescence spectra. Some of the extra lines have resolvable Cu hyperfine structure; they are assigned as transitions to levels which result from mixing essentially between ²_g(1/2) and a nearby ² Sigma _g state.

We have used an effective Hamiltonian to model the ²~~² Sigma interaction and derived molecular constants for the unknown ² Sigma state using a non-linear least-squares fitting routine. Taking an arbitrary value of the spin-orbit parameter A of -300 cm^-1, we estimate the ² Sigma state to lie around 3000 cm^-1 above the (0,0,0) level of the X²_g(3/2) ground state.