Interaction potentials for Br(2P)+Ar, Kr, and Xe (1S) by the crossed molecular beams method

Abstract

Angular distributions of Br(²P_3/2,1/2) scattered off Ar, Kr, and Xe (¹S₀) in the thermal energy range were measured in crossed molecular beams experiments. Interaction potentials for the X1/2 and I3/2 states are derived by using an approximate elastic scattering analysis, which neglects interstate coupling, as previously done for F–Xe, Kr, Ar, Ne and Cl–Xe. While the Br–Xe X1/2 potential (ε = 0.645 kcal/mole, r_m = 3.80 Å) shows a stronger interaction than the interaction potential of Kr–Xe, the Br–Kr (ε = 0.460 kcal/mole, r_m = 3.90 Å) and Br–Ar (ε = 0.380 kcal/mole, r_m = 3.73 Å) X1/2 potentials are closer to those of the corresponding rare gas pairs. The I3/2 potential for all three systems is found to have a shallower ε, a slightly larger r_m, and a more repulsive wall than the ¹Σ⁺ potential of the corresponding rare gas pair. The origin of these interactions is discussed and an attempt to examine the rare gas halides ground state bonding is presented.