Laser fluorescence excitation spectroscopy of the GeAr van der Waals complex

摘要

Laser fluorescence excitation spectra of the GeAr van der Waals complex, in the vicinity of the individual fine-structure lines of the Ge4s~24p5s~3P deg<-4s~24p~2 3P atomic resonance transition in the region 275-260 nm are reported. Excited-state (v',0) progressions of bands built upon the individual J'<-J" fine-structure atomic lines were observed. In all cases, the progressions terminated with a broad, unstructured band characteristic fo the existence of a barrier in the excited-state potential energy curves. Assignment of the v' vibrational quantum numbers for the resolved bands was successfully carried out through analysis of the ~70,72,74,76,76GeAr isotope splittings of the bands. Rotational analyses of the resolved bands were carried out, and upper- and lower-state OMEGA assignments and determination of the rotational constants could be performed. Transitions out of lower OMEGA"=0~+, 1, and 0~+ levels associated with the asymptotic Ge(4s~24p~2 ~3P) J"=0,1, and 2 atomic fine-structure levels, respectively, were observed. To derive information on the relevant Ge+Ar interactions, the observed spectra were interpreted through model potential energy curves based on the isoelectronic SiAr system. The large spin-orbit interaction of the Ge atom has a strong effect on the nonbonding interactions of the fine-structure levels with the Ar atom.