Eur. Phys. J. D 6, 333-341 (1999)
https://doi.org/10.1007/s100530050317

LiAr, LiKr and LiXe excimers: Photochemical formation of the 3²Σ⁺ -1²Σ⁺ bands

¹ Institute of Physics, P. O. Box 304, Zagreb, Croatia
² Department of Chemistry, Gorleaus Laboratory, University of Leiden, P. O. Box 9502, 2300 RA Leiden, The Netherlands
³ Max-Planck-Institut für Strömungsforschung, 37018-Göttingen, Germany

Received: 2 October 1998
Revised: 25 January 1999
Published online: 15 June 1999

Abstract

We investigated the photochemical formation of lithium-rare-gas excimers in the 3 state through the reaction of Li₂(2(C)) and the ground-state rare-gas atom. Lithium-rare-gas vapor mixture was prepared in the heat-pipe oven. We populated the 2(C) state of the Li₂ molecule using the XeCl excimer laser wavelength at 308 nm or the PTP dye laser wavelength at about 335 nm. The 3-1 transitions were observed with peaks at 414, 420 and 435 nm for LiAr, LiKr and LiXe, respectively. We estimated thermally averaged rate constants for these photochemical reactions, which are cm³s^-1 for LiAr, cm ³s^-1 for LiKr and cm³s^-1 for LiXe. Ab initio potential-energy curves and transition dipole moments for LiKr were calculated applying the SCF MRDCI method. Available data for the LiAr and LiKr excimers are presented, including potential-energy curves, electronic transition dipole moments, and spectroscopic constants. Possible photochemical formation of these molecules in the excited states is discussed. We performed the quantum-mechanical spectral simulations of the LiAr and LiKr 3-1 transitions, using ab initio potential-energy curves.