Zeeman relaxation induced by spin-orbit coupling in cold antimony-helium collisions

Abstract

We investigate Zeeman relaxation in cold Sb([superscript 4]S[subscript 3/2]∘)–He collisions in a magnetic field. Ensembles of >10[superscript 13] laser-ablated Sb atoms are cooled in cryogenic [superscript 4]He buffer gas to 800 mK and inelastic collisions are observed to equilibrate the m[subscript J]-state distribution to the translational temperature. The ratio γ of momentum transfer to inelastic collision rates is measured to be ⩽9.1×10[superscript 2]. We also perform quantum scattering calculations of Sb–[superscript 4]He collisions, based on ab initio interaction potentials, that demonstrate significant anisotropy of the ground state induced by the spin-orbit interaction. Agreement is obtained between theory and experiment with a ≈10% increase in the ab initio potential depth. This work suggests that buffer-gas-cooled pnictogen atoms lighter than Sb can be loaded into a magnetic trap.