VIBRATIONAL PREDISSOCIATION DYNAMICS OF THE (HEBR2)-BR-79, VAN-DER-WAALS MOLECULE NEAR THE B-STATE DISSOCIATION LIMIT - BINDING-ENERGIES, LIFETIMES, AND IMPLICATIONS FOR THE RARE GAS-HALOGEN POTENTIAL
Dg. Jahn et al., VIBRATIONAL PREDISSOCIATION DYNAMICS OF THE (HEBR2)-BR-79, VAN-DER-WAALS MOLECULE NEAR THE B-STATE DISSOCIATION LIMIT - BINDING-ENERGIES, LIFETIMES, AND IMPLICATIONS FOR THE RARE GAS-HALOGEN POTENTIAL, The Journal of chemical physics, 101(1), 1994, pp. 283-291
Excitation spectra of the (HeBr2)-Br-79 complex have been obtained for
the B state vibrational levels upsilon' = 34-48 using the pump-probe
spectroscopic technique. The Delta upsilon = - 1 channel for vibration
al predissociation is closed for levels upsilon'= 45 and higher. The B
and X state van der Waals binding energies are determined to be 13.5/-1.0 and 17.0+/-1.5 cm(-1), respectively. Lifetimes for vibrational p
redissociation were found to range from 5.3 ps for upsilon' = 34 to 1.
8 ps for upsilon' = 44. For upsilon' = 45 the lifetime increases to 3.
8 ps due to the closing of the Delta upsilon = - 1 dissociation channe
l. The lifetimes are consistent with the momentum gap law using a Mors
e parameter equal to 1.9+/-0.1 Angstrom(-1). The trend of increasing b
lue shifts as upsilon' increases reverses at upsilon' = 40. This appea
rs to indicate that the He-Br interaction changes dramatically when th
e Br-Br separation becomes larger than 4.0 Angstrom. Based on the resu
lts presented here, we have reevaluated previous data for the HeI2 mol
ecule, and suggest that the ground-state binding energy be revised to
17.6+/-1.0 cm(-1) from the currently accepted value of 18.8 cm(-1).