Münster 1999 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

CP: Chemische Physik

CP 26: Poster: Spektroskopie

CP 26.7: Poster

Montag, 22. März 1999, 18:00–20:00, R52/R72

Fluorescence from ionic excimer states of alkalihalides in solid Ne and Ar films — •G. Śliwiński¹, M. Frankowski¹, and N. Schwentner² — ¹Pol. Acad. Sci., IF-FM, Fiszera 14, PL 80-952 Gdańsk — ²Institut für Experimentalphysik, FU Berlin, Arnimallee 14, D-14195 Berlin

The electronic shell configurations of alkalihalide ions (A⁺X) correspond to those of rare gas halides RgX in the ground state and the charge transfer states (A²⁺X⁻) are isoelectronic to (Rg⁺X⁻) exciplex states with similar potential surfaces. The alkalihalide ionic systems A²⁺X⁻ are promissing for an extension of the solid state excimer lasers towards shorter wavelengths. Pulsed e-beam excitation of solid Ne and Ar films doped with 0.4 to 0.6 % (AX) leads to fluorescence in the VUV and deep UV region. The A²⁺X⁻ states are efficiently populated by ionisation of the trapped AX molecules via Rg excitons. The B²Σ→ X²Σ and C²Π→ A²Π bands of Cs²⁺F⁻ (196.5 nm, 227 nm), Cs²⁺Cl⁻ (220.1 nm, 249.2 nm) and Rb²⁺F⁻ (136 nm) in Ne, and a weaker (B-X) emission of Cs²⁺F⁻ (211.2 nm) in Ar are identified, respectively. The ratio of recorded intensities I(CsF)/I(CsCl)/I(RbF) = 20/5/1 reflects the energy transfer efficiency. For RbF and CsCl a competitive emission channel due to pre-dissociation in the B²Σ state is observed. An efficient formation of X₂ molecules (RbF, CsCl) is confirmed through recording the molecular D^′(³Π_2g) - A^′(³Π_2u) transition. A strong quenching occurs at doping concentrations higher than 0.7%.