Collisional processes in sodium vapour optically excited to the 3P state: asymptotic calculations

Studies two mechanisms for the non-resonant population of the sodium 4D state when sodium vapour is optically excited to the 3P state. They are the energy-pooling collision of two 3P-excited atoms and the radiative collision involving a laser photon. Both processes are considered in the region of large interatomic distances. Results are compared with experimental data.