Fine-structure changing collisions in atomic titanium

Fine-structure changing collisions are of interest for understanding interstellar evolution, and may play an important role in experiments with anisotropically- interacting atoms. We use helium buffer-gas cooling and optical pumping techniques to measure cold titanium--helium collisions that cause transitions between the fine- structure levels of the $[3d^2 4s^2] \ ^3F_J$ electronic ground state of atomic $^{48}$Ti, over a temperature range from 5 to 20 K. The Ti--He inelastic collision rate is strongly suppressed compared to collision rates of non-transition-metal atoms with noble gas atoms.