標題: The elusive excited states of bithiophene: a CASPT2 detective story
作者: Andrzejak, Marcin
Witek, Henryk A.
應用化學系
應用化學系分子科學碩博班
Department of Applied Chemistry
Institute of Molecular science
關鍵字: Excited states;Bithiophene;CASSCF;CASPT2;Vertical excitation energies;Absorption spectrum
公開日期: 1-五月-2011
摘要: A systematic multi-reference perturbation theory investigation of the excitation energies and oscillator strengths for the lowest excited states of 2,2'-bithiophene unequivocally shows that its optical spectrum is produced by two (1) B (u) states separated from each other by approximately 1 eV. This picture is confirmed by additional calculations with alternative quantum chemical methods. Our findings are in strong contrast with the previous CASPT2 results of Rubio et al. [J Chem Phys 102:3580 (1995) and Chem Phys Chem 4:1308 (2003)], who predicted that the two lowest (1) B (u) states are quasi-degenerate. The methodological reasons responsible for the previous seemingly erroneous assignment of the optical spectrum of bithiophene are identified and explained in terms of unusually large coupling between the (1) B (u) states introduced by dynamical correlation effects. A general discussion of applicable computational techniques is offered aiming at avoiding similar problems for other molecular systems.
URI: http://dx.doi.org/10.1007/s00214-011-0916-x
http://hdl.handle.net/11536/8954
ISSN: 1432-881X
DOI: 10.1007/s00214-011-0916-x
期刊: THEORETICAL CHEMISTRY ACCOUNTS
Volume: 129
Issue: 2
起始頁: 161
結束頁: 172
顯示於類別:期刊論文


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  1. 000289898800004.pdf