A combined quantum mechanical and molecular mechanical method using modified generalized hybrid orbitals: Implementation for electronic excited states

Yukio Kawashima, Haruyuki Nakano, Jaewoon Jung, Seiichiro Ten-Nod

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The generalized hybrid orbital (GHO) method is implemented at the second-order approximate coupled cluster singles and doubles (CC2) level for quantum mechanical (QM)/molecular mechanical (MM) electronic excited state calculations. The linear response function of CC2 in the GHO scheme is derived and implemented. The new implementation is applied to the first singlet excited states of three aromatic amino acids, phenylalanine, tyrosine, and tryptophan, and also bacteriorhodopsin for assessment. The results obtained for aromatic amino acids agreed well with the full QM CC2 calculations, while the calculated excitation energies of bacteriorhodopsin and its chromophore, all-trans retinal, reproduced the environmental shift of the experimental data. For the bacteriorhodopsin case, the environmental shift of GHO also showed good agreements with the experimental data. The contribution of the quantum effect of certain moieties in the excited states is elucidated by changing the partitioning of QM and MM regions.

Original languageEnglish
Pages (from-to)11731-11738
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume13
Issue number24
DOIs
Publication statusPublished - Jun 28 2011

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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