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Time‐dependent density functional calculations on the electronic spectra of the neutral nickel complex [Ni(L ISQ ) 2 ] (L ISQ = 3,5‐di‐ tert ‐butyl‐ o ‐diiminobenzosemiquinonate(1 − )) and its monoanion and dication
Author(s) -
Bachler Vinzenz
Publication year - 2009
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.21220
Subject(s) - dication , chemistry , density functional theory , singlet state , atomic physics , excited state , wave function , spectral line , ground state , ion , molecular electronic transition , electronic structure , diradical , nickel , open shell , computational chemistry , physics , quantum mechanics , organic chemistry
The electronic spectrum of the neutral nickel complex [Ni(L ISQ ) 2 ] (L ISQ = 3,5‐di‐ tert ‐butyl‐ o ‐diiminobenzosemiquinonate(1 − )) and the spectra of its anion and dication have been calculated by means of time‐dependent density functional theory. The electronic ground state of the neutral complex exhibits an open shell singlet diradical character. The mandatory multireference problem for this electronic ground state has been treated approximately by using the unrestricted and spin symmetry broken Kohn‐Sham Slater determinant as the wave function for the noninteracting reference system in the time‐dependent density functional calculations. A reasonable agreement with observed transition energies and band intensities has been achieved. This holds also for the long wavelength transitions that are shown to be of charge transfer type. The charge distributions in the electronic ground state and the corresponding low lying excited states, however, are rather similar. Thus, the known failure of standard time‐dependent density functional theory to describe improperly long range charge transfer transitions is absent in this work. The applied computational scheme might be adequate for calculating electronic spectra of transition metal complexes with noninnocent ligands. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009