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Electronic excitations of the green fluorescent protein chromophore in its protonation states: SAC/SAC‐CI study
Author(s) -
Das Abhijit K.,
Hasegawa JunYa,
Miyahara Tomoo,
Ehara Masahiro,
Nakatsuji Hiroshi
Publication year - 2003
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.10308
Subject(s) - protonation , chromophore , excited state , chemistry , ground state , fluorescence , excitation , photochemistry , homo/lumo , absorption (acoustics) , molecular physics , atomic physics , physics , molecule , quantum mechanics , optics , ion , organic chemistry
Two ground‐state protonation forms causing different absorption peaks of the green fluorescent protein chromophore were investigated by the quantum mechanical SAC/SAC‐CI method with regard to the excitation energy, fluorescence energy, and ground‐state stability. The environmental effect was taken into account by a continuum spherical cavity model. The first excited state, HOMO‐LUMO excitation, has the largest transition moment and thus is thought to be the source of the absorption. The neutral and anionic forms were assigned to the protonation states for the experimental A‐ and B‐forms, respectively. The present results support the previous experimental observations. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1421–1431, 2003