15min:

SARA E. RAY AND ANNE B. MCCOY, Department of Chemistry, The Ohio State University, Columbus, OH 43210; JOHN M. HERBERT, Department of Chemistry, University of California, Berkeley, CA 94720.

The rovibronic (B X) transitions of He Br₂ and He I₂ have been studied through calculations of the energies of the bound states on the X and B state potential surfaces. In these studies, literature potentials are used for all but the X-state of He Br₂.\footnoteM. P. de Lara-Castells, A. A. Buchachenko, G. Delgado-Barrio, and P. Villarreal, J. Chem. Phys. \underline 120, 2182 (2004).\footnoteR.Prosmiti, A. Valdes, P. Villarreal, and G. Delgado-Barrio, J. Chem. Phys. \underline 108, 6065 (2004). In that case, we calculated the potential at the CCSD(T) level of theory using the SDD+G(3df) basis for Br, the aug- cc-pVQZ basis for He, and a 3s3p2d2f1g set of bond functions, optimized for rare-gas molecule interactions,\footnoteS. M. Cybulski and R. R. Toczylowski, J. Chem. Phys. \underline 111, 10520 (1999). centered at the midpoint between He and the Br₂ center of mass. Using these potentials, the energies and wave functions of the bound states of the complexes are generated for J\le 9. From these results, the vibronic spectra are computed over a range of temperatures from 0.1 to 2.5 K. Excellent agreement with the reported spectra is obtained.