Ab initio calculations of energy transfer and non-additivity in the He-Ne laser system
Department of Chemistry, Faculty of Science, Benha University, Benha, Egypt
2 Departments of Physics, Faculties of Education and Science, Ain Shams University, Cairo, Egypt
Revised: 20 March 1999
Published online: 15 September 1999
Ab initio calculations were performed for several suggested mechanisms of energy transfer between helium metastable particles and neon. Optimized geometries and excited-state energies were calculated for neon excited-state complexes and the convergence properties of the non-additive contributions to the interaction energies were examined. The most probable excitation-transfer mechanism was found to be based on an energy difference of 0.0674 eV between the triplet excited state of and the singlet excited state of . No theoretical evidence was found for the production of neon singlet excited-state complexes other than 20.0858 to 20.4875 eV by the considered two-, three- and four-body models of energy transfer processes. The energy curves of the reactions involving the excited-state complexes and are provided and compared with the previously reported experimental results on the reaction . The relation between the probability of energy transfer and laser activity is discussed. The non-additive contribution to the total interaction energy of the nominated intermediate complex was found to be negligible, pointing to the possibility of constructing model potentials and simulation of larger systems.
PACS: 34.20.-b – Interatomic and intermolecular potentials and forces, potential energy surfaces for collisions / 31.30.-i – Corrections to electronic structure / 31.50.+w – Excited states
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999