Collisional relaxation of vibrational states of SrOH with He at 2 K

Abstract

Vibrational relaxation of strontium monohydroxide (SrOH)molecules in collisions with helium (He) at 2Kis studied.Wefind the diffusion cross section of SrOHat 2.2 K to be σd = (5 ± 2) × 10-14 cm2 and the vibrational quenching cross section for the (100) Sr-Ostretchingmode to be σq = (7 ± 2) × 10-17cm2.The resulting ratio γ100 = σd σq ∼ 700 ismore than an order ofmagnitude smaller than for previously studied few-atom radicals (Au et al 2014 Phys.Rev.A90 032703 ).We also determine the Franck-Condon factor for SrOH (Ã π1/2 (100) ← X2 ∑+ (000)) to be (4.8 ± 0.8) × 10-2.