Abstract
The electronic vertical excitation energies for singlet and triplet valence, and Rydberg states of trans-buta-1,3-diene have been computed using ab initio multi-reference multi-root CI procedures with a [4s3p3d3f] set of Rydberg functions. Close numerical agreement between theory and experiment was found for a number of low-lying electronic states. The present CI and CASSCF [8MO,8e] calculations suggest that both the vertical and adiabatic order of the valence (pp) states is: A1Ag<B1Bu. An electron energy-loss spectrum, reported here, in which the incident electrons have near-threshold energies, supports this order. Adiabatic excitation energies and structures were obtained for several singlet and triplet states using CASSCF and B3LYP procedures; the results from these methods are generally in good agreement with each other. The C1C2 to C2C3 bond length ratio in the excited states varies widely, and is discussed. © 2010 Elsevier B.V. All rights reserved.
Original language | English |
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Pages (from-to) | 159-169 |
Number of pages | 11 |
Journal | Chemical Physics |
Volume | 373 |
Issue number | 3 |
DOIs | |
Publication status | Published - 3 Aug 2010 |
Keywords
- Buta-1,3-diene: energy levels
- EEL spectrum
- Excited state energies and structures
- Photoelectron spectrum
- VUV spectrum