15min:

DAVID B. STRASFELD, JOSHUA P. DARR AND RICHARD A. LOOMIS, Department of Chemistry, Washington University, One Brookings Drive, CB 1134, Saint Louis, MO 63130; ANNE B. MCCOY, Department of Chemistry, The Ohio State University, Columbus, OH 43210.

Multiple features associated with transitions of the near T-shaped and linear Ne I^35,37Cl( X , v ''=0) isomers are observed in laser-induced fluorescence spectra recorded in the ICl B - X , 2-0 and 3-0 spectral regions. The T-shaped complexes access the lowest intermolecular vibrational level within the Ne + ICl( B , v ') potential, while the linear complexes access at least four different bending levels that are delocalized in the angular coordinate. The ground state binding energy of the linear Ne I³⁵Cl isomer is directly measured in two-laser, action spectroscopy experiments. A continuum signal is observed with a turn on at 17 748.4 cm^-1 that indicates a binding energy of 84.3(2.3) cm^-1 for the ground state complex. The ground state binding energy of the T-shaped isomer can be estimated by fitting the Ne I³⁵Cl( B , v '=2) bending levels that the ground state linear isomer accesses to an _e, _{e e} progression. The fit reveals a binding energy of 60.8(3.2) cm^-1 for Ne I³⁵Cl( B , v '=2), which implies a T-shaped ground state binding energy of 66.2(3.2) cm^-1 based upon the spectroscopic shift of the T-shaped feature from the I³⁵Cl B - X , 2-0 transition. Two-laser, pump-probe experiments were also performed to access the intermolecular vibrational levels that are bound within the Ne + ICl( E 0⁺, v =10) ion-pair state. In these experiments, the pump laser was fixed on either the lowest energy level, with a T-shaped equilibrium geometry, or one of the higher energy delocalized levels within the Ne + I³⁵Cl( B , v '=2) well. In this manner, varying Ne I³⁵Cl Franck-Condon windows between the B and E states are accessed and assignments of the intermolecular vibrational levels within the ion-pair state can be made. The results suggest a Ne + ICl( E 0⁺) potential with the lowest bound level localized in the T-shaped orientation and that the higher energy levels are delocalized in the angular coordinate.