  We have obtained accurate ab initio quartet potentials for the diatomic
metastable triplet helium + alkali-metal (Li, Na, K, Rb) systems, using
all-electron restricted open-shell coupled cluster singles and doubles with
noniterative triples corrections [CCSD(T)] calculations and accurate
calculations of the long-range $C_6$ coefficients. These potentials provide
accurate ab initio quartet scattering lengths, which for these many-electron
systems is possible, because of the small reduced masses and shallow potentials
that results in a small amount of bound states. Our results are relevant for
ultracold metastable triplet helium + alkali-metal mixture experiments.
