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| Hauptseite > Publikationsdatenbank > MR-CISD and MR-AQCC calculation of excited states of Malonaldehyde: Geometry optimizations using analytical energy gradient methods and a systematic investigation of reference configuration sets |
| Hauptseite > Publikationsdatenbank > MR-CISD and MR-AQCC calculation of excited states of Malonaldehyde: Geometry optimizations using analytical energy gradient methods and a systematic investigation of reference configuration sets |
| Journal Article | PreJuSER-28420 |
; ; ;
2003
Institute of Organic Chemistry and Biochemistry, Prague
Prague
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Please use a persistent id in citations: doi:10.1135/cccc20030447
Abstract: Extended MR-CISD and MR-AQCC calculations have been performed on the ground state and the first two excited states of malonaldehyde. Full geometry optimizations have been carried for C-s and C-2v structures both at MR-CISD and MR-AQCC levels. Vertical and minimum-to-minimum excitation energies and oscillator strengths have been computed. Systematic studies have been undertaken concerning several types of reference spaces. Agreement with the experimental 0-0 transition energy to the S-1 state (expt. 3.50 eV, calc. 3.56 eV) and for the vertical excitation to S-2 (expt. band maximum 4.71 eV, best estimate 4.86 eV) is very good. In agreement with the CASSCF/CASPT2 results by Sobolewski and Domcke (J. Phys. Chem. A 1999, 103, 4494), we find that the hydrogen bond in malonaldehyde is weakened by excitation to the S-1 state. The barrier for proton transfer in the S-1 state is increased in comparison with the ground state.
Keyword(s): J ; excited states (auto) ; multireference configuration interaction (auto) ; proton transfer (auto) ; hydrogen bond (auto) ; malonaldehyde (auto) ; ab initio calculations (auto)
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