@article {2585, title = {Collisions of room-temperature helium with ultracold lithium and the van der Waals bound state of HeLi}, journal = {Phys. Rev. A }, volume = {101}, year = {2020}, month = {1/6/2020}, abstract = {

We have computed the thermally averaged total, elastic rate coefficient for the collision of a room-temperature helium atom with an ultracold lithium atom. This rate coefficient has been computed as part of the characterization of a cold-atom vacuum sensor based on laser-cooled Li 6 or Li 7 atoms that will operate in the ultrahigh-vacuum (p\< 10\− 6 Pa) and extreme-high-vacuum (p\< 10\− 10 Pa) regimes. The analysis involves computing the X 2 Σ+ HeLi Born-Oppenheimer potential followed by the numerical solution of the relevant radial Schr{\"o}dinger equation. The potential is computed using a single-reference-coupled-cluster electronic-structure method with basis sets of different completeness in order to characterize our uncertainty budget. We predict that the rate coefficient for a 300 K helium gas and a 1 μ K Li gas is 1.467 (13)\× 10\− 9 cm 3/s for He 4+ Li 6 and 1.471 (13)\× 10\− 9 cm 3/s for He 4+ Li 7, where the \…

}, doi = {https://doi.org/10.1103/PhysRevA.101.012702}, author = {Constantinos Makrides and Daniel S Barker and James A Fedchak and Julia Scherschligt and Stephen Eckel and Eite Tiesinga} }