Nonmetastable Penning ionization inHe(3P1)-Ne, Ar, Kr, Xe collisions

Time-dependent spectroscopy techniques have been used to determine the cross sections for the deexcitation of nonmetastable $\mathrm{He}\left(3\mathrm{}{}_{}{}^1{}_{}{}^{}P\right)$ states by collision with Ne, Ar, Kr, or Xe atoms. The measured cross sections in ${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$ at ${600}_{-100\mathrm{}}^{+200\mathrm{}}$ °K are, for Ne, ${27.6}_{-2.8\mathrm{}}^{+4.5\mathrm{}}$; Ar, ${55.6}_{-7.8\mathrm{}}^{+10.6\mathrm{}}$; Kr, ${49.5}_{-4.8\mathrm{}}^{+8.0\mathrm{}}$; and Xe, ${73.0}_{-8.8\mathrm{}}^{+12.9\mathrm{}}$. These cross sections are compared with theoretical Penning ionization cross sections having values of 20 for Ne, 40 for Ar, 39 for Kr, and 35 for Xe, in units of ${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$ (at 600 °K).