Scattering of Stark-decelerated OH radicals with rare-gas atoms

Abstract

We present a combined experimental and theoretical study on the rotationally inelastic scattering of OH (X 2 Π 3/2 , J = 3/2, f ) radicals with the collision partners He, Ne, Ar, Kr, Xe, and D2 as a function of the collision energy between ∼ 70 cm −1 and 400 cm −1 . The OH radicals are state selected and velocity tuned prior to the collision using a Stark decelerator, and field-free parity-resolved state-tostate inelastic relative scattering cross sections are measured in a crossed molecular beam configuration. For all OH-rare gas atom systems excellent agreement is obtained with the cross sections predicted by close-coupling scattering calculations based on accurate ab initio potential energy surfaces. This series of experiments complements recent studies on the scattering of OH radicals with Xe [Gilijamse et al., Science 313, 1617 (2006)], Ar [Scharfenberg et al., Phys. Chem. Chem. Phys. 12, 10660 (2010)], He, and D2 [Kirste et al., Phys. Rev. A 82, 042717 (2010)]. A comparison of the relative scattering cross sections for this set of collision partners reveals interesting trends in the scattering behavior.PACS. PACS-key discribing text of that key -PACS-key discribing text of that key

The hyperfine excitation of OH radicals by He

“…This is in agreement with numerous previous studies of rotational cross sections in OH(X) + He [14,[27][28][29]. This spin-orbit propensity is not as important as in other systems such as NO(X) + He [30,31]. One can clearly see that there is a strong propensity in favor of Δj = ΔF transitions for spin-orbit conserving transitions.…”

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

“…Close-coupling calculations were performed both with the HIBRIDON suite of programs [33], and with a second independent scattering program for open-shell diatom-atom scattering described in Ref. 34. Care was taken to independently check the results with the two scattering programs and to converge the cross sections.…”

“…We note that in Ref. 34 sis set for the coupled-cluster calculations of the interaction energy from the augmented triple-zeta correlationconsistent basis set (AVTZ) used by Lee et al [26] to the quintuple-zeta basis set (AV5Z). We computed the interaction energies with the open-shell single and double excitation coupled cluster method with perturbative triples as implemented in the molpro package [35].…”

Resonances in rotationally inelastic scattering of NH3 and ND3 with H2

“…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.…”