Hyperfine-changing collisions in an optically trapped gas of ultracold cesium and lithium

The rate coefficients for hyperfine-changing collisions of ground-state 133Cs and 7Li atoms trapped in a quasielectrostatic trap (QUEST) were investigated. The rate coefficients G(4,4) for hyperfine-changing collisions of Cs atoms in the upper hyperfine ground state |F=4 was found to be 1.1 x 10-11 cm3s-1 in the temperature range between 30 and 130 K. Absorption imaging was used to detect the Cs atom number, density and temperature. It was concluded that the behavior of a mixture of Li and Cs atoms that was analyzed using coupled rate equations can result the rate coefficients for all possible combinations of hyperfine ground states