Quenching of Li low-n Rydberg atoms by ground-state He atoms: A low-energymolecular-state calculation - art. no. 032709

Total cross sections for quenching of low-n Rydberg states of Li (n<10, l=0 ) in collision with the ground stare He have been calculated in the low-ene rgy region (v less than or equal to 0.1 a.u.) by employing the molecular or bital approximation. Results for the total depopulation of the parent state s, along with those for excitation arid de-excitation mechanisms have been presented. Present cross sections exhibit the low-energy Stueckelberg oscil lations. Using a model two-state calculation we present a detailed comparat ive study between the quantum-mechanical and semiclassical findings. Except at very low energies, the semiclassical cross sections agree nicely with t heir quantum counterparts. The reaction rates at thermal energies are also reported.