Elastic and Inelastic Scattering of 2 3 S Metastable and Ground State Helium Atoms

I. Ya. Fugol’

Hellmut Haberland, Bernhard Brutschy, K.‐H. Schmidt

Joachim Großer, Hellmut Haberland

V. Kartazaev, Yu. A. Piotrovskii, Yu. A. Tolmachev

Stephen Evans

Prabal K. Sinha, Arnab Ghosh

Quantal calculations for scattering of ground-state antihydrogen by metastable $(n=2S)$ helium atoms have been performed using the nonadiabatic, atomic orbital expansion technique at thermal energies. The zero-energy elastic cross sections of the present systems are much greater than the corresponding value for the ground-state helium target. The low-energy elastic cross section for the singlet metastable helium $[\mathrm{He}(2\phantom{\rule{0.2em}{0ex}}^{1}S)]$ target is higher than the corresponding value when the target is in the metastable triplet state $[\mathrm{He}(2\phantom{\rule{0.2em}{0ex}}^{3}S)]$.