| Autor: |
Robertson, Evan G., Thompson, Christopher D., Morrison, Richard J. S. |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 12/22/2004, Vol. 121 Issue 24, p12421-12427, 7p, 2 Diagrams, 3 Charts, 6 Graphs |
| Abstrakt: |
The S1←S0 transition of 1-phenylimidazole (1PI) has been studied in a supersonic jet expansion by resonant two-photon ionization. The origin band at 36 075 cm-1 is accompanied by a low frequency progression associated with torsion about the bond connecting phenyl and imidazole groups. Torsional potentials have been determined for both states. In S0, [lowercase_phi_synonym]min=37.2±0.5° and the planar barrier is 339±20 cm-1, while in S1, [lowercase_phi_synonym]min=17.6±0.5° and the planar barrier is 57±2 cm-1. The transition moment alignment is observed to be consistent with an excited state of Lb character, in spite of the “off-axis” conjugation provided by the imidazole ring. These results are compared with ab initio calculations on both states, performed using Hartree–Fock, Møller–Plesset second-order perturbation, density functional theory with the Becke3–Lee–Yang–Parr functional, time-dependant density functional theory, configuration interaction singles, and complete active space self-consistent field methods. Solution-phase UV spectra of neutral and protonated 1PI are also reported.© 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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