Konstanz 1998 – scientific programme

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MO: Molekülphysik

MO 10: Poster: Spektroskopie, Photodiss., Theorie

MO 10.28: Poster

Wednesday, March 18, 1998, 16:00–18:00, PF

Non-adiabatic Predissociation of IBr — •S. Stolte, A.E. Wiskerke, R. Mooijman, and E.A. Volkers — Dept. of Chemistry, Laser Centre, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands

The frequency dependence of predissociation in the [...] transition is studied using a narrow-banded pulsed dye-laser and a molecular beam. In this experiment, we use a (NdYAG pumped) pulsed dye laser for photo dissociation of IBr. Iodine atoms, formed by the predissociative [...] state, were detected resonant ionisation with 304 nm light produced by the second harmonic of a second dye laser fired 400 ns later. In addition, a time of flight technique was used for mass specific detection. Preceding experiments employing femtosecond lasers uncovered a complicated wave packet evolution during dissociation which can be ascribed to a intermediate diabatic/adiabatic coupling between the bound [...] and the repulsive [...] potential energy curves. This intermediate coupling case leads to a very fast dissociation in the range from 560nm where the vibrational energy equals the I+Br* threshold. In the present study, the fast predissociation rate is connected to extremely large line widths. The results of this frequency resolved study will be compared to the time resolved fs study. Furthermore, quantative information about the two potential energy surfaces and the coupling can be extracted.