Eur. Phys. J. D 65, 383-390 (2011)
https://doi.org/10.1140/epjd/e2011-20104-6

Regular Article

Cold and ultracold collisions of MgH (2Σ+) with helium

Department of Physics, Anhui normal university, Wuhu 241000, P.R. China

^a e-mail: fengbf@mail.ahnu.edu.cn

Received: 12 February 2011
Received in final form: 24 May 2011
Published online: 22 November 2011

Abstract

The cross sections for rotational, fine-structure and projection-change transitions in collision of MgH (²Σ⁺) molecule with ³He and ⁴He atoms were computed at cold and ultracold temperatures using the ab initio potential energy surface. The significant suppression feature and resonance pattern caused by spin-rotation interaction were found and discussed. The collisions exhibit a strong isotope effect in the ultracold regime. The rotational relaxations of the fine-structure excited energy levels tendentiously preserve the F index. The ratio of the cross sections for elastic and spin-flipping collision with ³He partner is always greater than seven orders of magnitude for the energy range 10^-6−1cm^-1 and suggests the MgH molecule is a good candidate for ³He buffer gas cooling.