Berlin 2001 – scientific programme
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MO: Molekülphysik
MO 8: Posters Thursday: Dissociation and other Collision Processes
MO 8.20: Poster
Thursday, April 5, 2001, 12:30–15:00, AT3
Investigation of the neutral photodissociation of the O2 molecule via the decay of the 2σu−1 (c4Σu−)n σg Rydberg states — •H. Liebel1, Ph.V. Demekhin2, B.M. Lagutin2, I.D. Petrov2, V.L. Sukhorukov2, A. Ehresmann1, and H. Schmoranzer1 — 1FB Physik, Universität Kaiserslautern, D-67653 Kaiserslautern, Germany — 2Rostov State University of TC, 344038 Rostov-on-Don, Russia
At present there are two models for the predissociation of the 2σu−1 (c4Σu−) state of O2+. The ’slow’ model is based on the calculations of [1] and provides 2 · 10−8 s and 5 · 10−11 s for the predissociation lifetimes Tdv of the vibrational levels v=0 and v=1, respectively. The ’fast’ model is based on the pulsed electric field ionisation measurements [2] and gives Td0=2.7(3) · 10−13 s and Td1=6.9(7)· 10−14 s. We studied the fluorescence yield of the atomic Rydberg states OI 2p3 (4 So)n l which arise from the predissociation of the 2σu−1 (c4Σu−)n σg molecular Rydberg states (MRS). Using the measured absolute emission cross sections (CS) and the widths of the molecular Rydberg state peaks in these CS we were able to compare the predissociation lifetimes with those for Auger decay of the MRS. Calculations performed in the present paper with the use of potential curves from [3] show a good overall agreement between the measured widths as well as the emission CS and support the ’fast’ predissociation model yielding Td0=3.4· 10−12 s and Td1=6.3· 10−14 s.
[1] K. Tanaka, M. Yoshimine, J. Chem. Phys. 70 (1979) 1626.
[2] M. Evans et al., J. Chem. Phys. 109 (1998) 1285.
[3] N.H.F Beebe et al., J. Chem. Phys. 64 (1976) 2080.