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Hybrid QM/MM studies on energetics of malonaldehyde in condensed phase
Author(s) -
Shigeta Yasuteru
Publication year - 2003
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10790
Subject(s) - chemistry , dihedral angle , excited state , excitation , qm/mm , hydrogen bond , energetics , molecule , atom (system on chip) , hydrogen atom , ground state , planar , computational chemistry , crystallography , atomic physics , molecular dynamics , physics , thermodynamics , group (periodic table) , organic chemistry , quantum mechanics , computer science , embedded system , computer graphics (images)
Energetics of eight enol isomers of a malonaldehyde (MA) at the ground state in CCl 4 solvent environment have been investigated using a hybrid quantum mechanical (QM)/molecular mechanics (MM) method. It is found that relative energies of the isomers slightly change due to interactions between MA and surrounding atoms. In an isolated environment all eight isomers have stable planar structure. On the other hand, most of the isomers have nonplanar structure in CCl 4 whose interactions with the solute molecules are, however, weak. Mainly, structural changes are found in the HOCC dihedral angle ϕ HOCC , i.e., a hydrogen atom that is connected directly with an oxygen atom, is located at a nonplanar position, and other atoms remain almost planar. Vertical excitation energies of low‐lying excited states at the resultant optimized structure of each isomer are evaluated. The vertical excitation energies in CCl 4 are almost the same as those in the isolated environment, but some changes were found in the triplet excitation states. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004