Forrey, Robert C.Dalgarno, AlexVanne, Yulian V.Saenz, AlejandroFroelich, Piotr2019-09-272007Forrey, Robert C., Alex Dalgarno, Yulian V. Vanne, Alejandro Saenz, and Piotr Froelich. 2007. “Nonadiabatic Coupling in Cold Collisions of Spin-Polarized Metastable Hydrogen Atoms.” Physical Review A 76 (5). https://doi.org/10.1103/physreva.76.052709.1050-29471094-1622http://nrs.harvard.edu/urn-3:HUL.InstRepos:41417418Previous calculations of low-temperature cross sections for collisions between spin-polarized metastable hydrogen atoms are improved to include nonadiabatic radial and angular coupling at large interatomic separations. The electrostatic dipole-quadrupole interaction produces nonadiabatic radial coupling between (2s,2p) and (2p,2p) states, while the Coriolis interaction produces nonadiabatic angular coupling. Both of these long-range contributions are handled in a space-fixed atomic gauge that is particularly convenient for a spin-polarized system. The improved theoretical results are compared with an existing experiment.en-USJournal Article2019-09-2710.1103/PhysRevA.76.052709