Resonances in rotationally inelastic scattering of OH(X2Π) with helium and neon

Abstract

We present detailed calculations on resonances in rotationally and spin-orbit inelastic scattering of OH (X 2 Π, j = 3/2, F1, f ) radicals with He and Ne atoms. We calculate new ab initio potential energy surfaces for OH-He, and the cross sections derived from these surfaces compare favorably with the recent crossed beam scattering experiment of Kirste et al. [Phys. Rev. A 82, 042717 (2010)]. We identify both shape and Feshbach resonances in the integral and differential state-tostate scattering cross sections, and we discuss the prospects for experimentally observing scattering resonances using Stark decelerated beams of OH radicals.

Resonances in rotationally inelastic scattering of NH3 and ND3 with H2

“…8. The pattern of increased backward scattering at energies close to a resonance, as we found for the OH/NH 3 -rare gas systems, 10,11 is less clear for NH 3 …”

“…10,11,44,46 The availability of two totally distinct codes provided an ideal check of the accuracy and convergence of our calculations. We included in the closecoupling channel basis all para rotational levels of NH 3 with j ≤ 6 or E rotational levels of ND 3 with j ≤ 7.…”

“…IV C of Ref. 10. Here, we diagonalize the Hamiltonian exclusive of the radial kinetic energy for a given partial wave to obtain adiabatic bender curves.…”

“…[9][10][11] Scattering resonances have been observed in mostly atomic, elastic collisions [12][13][14] and in the reactive F + HD → HF + D system. 15 Recently, in a merged-beam geometry, shape (also called orbiting) resonances were seen in Penning ionization collisions of metastable helium atoms with argon atoms or H 2 molecules at collision energies as low as 0.01 K. 16,17 Both shape and Feshbach resonances were observed in rotationally inelastic atommolecule and molecule-molecule collisions.…”

“…Inspired by this possibility, our groups have searched theoretically for scattering resonances in the OH-He/Ne and the NH 3 -He systems in calculations based on state-of-the-art PESs. 10,11 Both these systems manifest significant shape and Feshbach resonances. The features are narrow, with widths of ∼1 cm −1 .…”