TY - JOUR AU - doMonte, S. A. AU - Dallos, M. AU - Müller, T. AU - Lischka, H. TI - 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 JO - Collection of Czechoslovak chemical communications VL - 68 SN - 0010-0765 CY - Prague PB - Institute of Organic Chemistry and Biochemistry, Prague M1 - PreJuSER-28420 SP - 447 - 462 PY - 2003 N1 - Record converted from VDB: 12.11.2012 AB - 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. KW - J (WoSType) LB - PUB:(DE-HGF)16 UR - <Go to ISI:>//WOS:000181709100002 DO - DOI:10.1135/cccc20030447 UR - https://juser.fz-juelich.de/record/28420 ER -