Wenge, Andreas Maximilian and Kensy, Uwe and Dick, Bernhard (2010) The photodissociation dynamics of N-nitrosopyrrolidine from the first and second excited singlet states studied by velocity map imaging. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 12 (18). pp. 4644-4655. ISSN 1463-9076, 1463-9084
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The photodissociation reaction of N-nitrosopyrrolidine isolated and cooled in a supersonic jet has been studied following excitation to the S-1 and S-2 electronic states. The nascent NO ((X) over tilde (2)Pi(1/2,3/2), v, j) radicals were ionized by state-selective (1 + 1)-REMPI via the A(2)Sigma(+) state. The angularly resolved velocity distribution of these ions was measured with the velocity-map imaging (VMI) technique. Photodissociation from S-1 produces NO in the vibrational ground state and the pyrrolidine radical in the electronic ground state 1 B-2. About 73% of the excess energy is converted into kinetic energy of the fragments. The velocity distribution shows a strong negative anisotropy (beta = -0.9) in accordance with the n pi*-character of the S-0 -> S-1 transition. An upper limit for the N-NO dissociation energy of (14 640 +/- 340) cm(-1) is determined. We conclude that photodissociation from S-1 occurs very fast on a completely repulsive potential energy surface. Excitation into the S-2 pi pi*-state leads to a bimodal velocity distribution. Two dissociation channels can be distinguished which show both positive anisotropy (beta = 1.3 and 1.6) but differ considerably in the total kinetic energy and the rotational energy of the NO fragment. We assign one channel to the direct dissociation on the S-2 potential energy surface, leading to pyrrolidine radicals in the excited electronic state 1 (2) . The second channel leads to pyrrolidine in the electronic ground state 1 B-2, presumably after crossing to the S-1 state via a conical intersection.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | TERT-BUTYL NITRITE; GAS-PHASE; INVERSION; DIMETHYLNITROSAMINE; NITROSAMINES; ABEL; PHOTOLYSIS; CLUSTERS; NITROSODIMETHYLAMINE; DIMETHYLAMINE; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry III - Physical Chemistry (Molecular Spectroscopy and Photochemistry) > Prof. Dr. Bernhard Dick |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 24 Aug 2020 07:58 |
| Last Modified: | 24 Aug 2020 07:58 |
| URI: | https://pred.uni-regensburg.de/id/eprint/25593 |
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