# Mechanism of Collisional Spin Relaxation in $$^3$$Σ Molecules

 Title: Mechanism of Collisional Spin Relaxation in $$^3$$Σ Molecules Author: Campbell, Wesley C.; Tscherbul, Timur V.; Lu, Hsin-I; Tsikata, Edem; Krems, Roman V.; Doyle, John M. Note: Order does not necessarily reflect citation order of authors. Citation: Campbell, Wesley C., Timur V. Tscherbul, Hsin-I Lu, Edem Tsikata, Roman V. Krems, and John M. Doyle. 2009. Mechanism of collisional spin relaxation in $$^3$$Σ molecules. Physical Review Letters 102(1): 013003. Full Text & Related Files: PRL.102.013003.pdf (283.9Kb; PDF) Abstract: We measure and theoretically determine the effect of molecular rotational splitting on Zeeman relaxation rates in collisions of cold $$^3$$Σ molecules with helium atoms in a magnetic field. All four stable isotopomers of the imidogen (NH) molecule are magnetically trapped and studied in collisions with $$^3$$He and $$^4$$He. The $$^4$$He data support the predicted 1/B$$^{2}_{e}$$ dependence of the collision-induced Zeeman relaxation rate coefficient on the molecular rotational constant B$$_e$$. The measured $$^3$$He rate coefficients are much larger than the $$^4$$He coefficients, depend less strongly on B$$_e$$, and theoretical analysis indicates they are strongly affected by a shape resonance. The results demonstrate the influence of molecular structure on collisional energy transfer at low temperatures. Published Version: doi:10.1103/PhysRevLett.102.013003 Other Sources: http://arxiv.org/PS_cache/arxiv/pdf/0804/0804.0265v2.pdf Terms of Use: This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:5349606 Downloads of this work: