Processes of quenching of excited He (2 1 P, 2 1 S) atoms by atoms of II group metals

David W. Fahey, L. D. Schearer

S. V. Kasyanenko, G. M. Malyshev, Yu. A. Tolmachev

J. Cooper, J. Coutts

Abstract : This report describes work addressing the problems of collisional induced oscillator strength and energy transfer from metastable states in Group IIA alkaline earth metal atoms. The quenching of CA 3PJ states when perturbed by rare was atom collisions is investigated and such quenching is found to be negligable. The CA 1D2 state, however shows considerable collisional induced effects. Calculations have been performed which show that collision cross-sections for transfer of electronic excitation may be switched from the low values typically associated with off-resonant processes to the high values associated with resonant processes by using a strong laser to bring dressed states in one atom in and out of resonance with bare states in another atom. Keywords: Slow atomic collisions; Chemical lasers.

S. V. Kasyanenko, G. M. Malyshev, Yu. A. Tolmachev

M. L. Yanson

An investigation was made of the mechanisms of quenching of excited states and of excitation of atomic levels as a result of absorption of laser radiation by alkali metal (Na, K, Cs) vapors. It was found that several processes participated in the excitation of atomic levels: collisional mechanism of excitation energy transfer from molecules to atoms, photodissociation, predissociation, and nonresonant excitation of atomic levels (radiative collisions). The partial contribution of each of these processes (dependent on the vapor density, intensity of laser radiation, and its frequency) should be allowed for in the balance of the filling and deactivation of molecular and atomic states. Qualitative characteristics were obtained for these processes and an analysis was made of their likely role in the emission of radiation from diatomic molecules in alkali metal vapors.

V. A. Kostenko, Yu. A. Tolmachev