Reinvestigation of the Rb 2 ( 2 ) Π 3 g − a Σ 3 u + band on helium nanodroplets

• Published in: The Journal of chemical physics 2010-02, Vol.132 (5), p.054304-054304-7
• Main Authors: Auböck, G., Aymar, M., Dulieu, O., Ernst, W. E.
• Format: Article
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.3308493

It is well known that alkali-metal molecules are preferentially observed in the weak van der Waals-bound high spin states by helium droplet isolation spectroscopy. In [ F. R. Brühl , J. Chem. Phys. 115 , 10275 ( 2001 ) ] the Rb 2 ( 2 ) Π 3 g − a Σ 3 u + band on He droplets was investigated by laser-induced fluorescence and dispersed emission spectroscopy. At that time no information on the magnitude of spin-orbit coupling was available for the ( 2 ) Π 3 g state which connects to the atomic 5 s + 4 d asymptote and it was neglected. In this work we reinvestigate the observed spectra. The dispersed emission spectra, which resulted from free molecules, are consistent with state-of-the-art nonrelativistic potential energy surfaces and effective spin-orbit coupling matrix elements obtained from resonance-enhanced multiphoton ionization spectroscopy of cold Rb dimers [ J. Lozeille , Eur. Phys. J. D 39 , 261 ( 2006 ) ]. Having validated the theoretical description of the free molecule state, we use the laser-induced fluorescence spectrum to discuss the influence of the He droplet on the excitation band.