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Title: Assessment of TD-DFT and LF-DFT for study of d − d transitions in first row transition metal hexaaqua complexes

Herein, we present the systematic, comparative computational study of the d − d transitions in a series of first row transition metal hexaaqua complexes, [M(H{sub 2}O){sub 6}]{sup n+} (M{sup 2+/3+} = V {sup 2+/3+}, Cr{sup 2+/3+}, Mn{sup 2+/3+}, Fe{sup 2+/3+}, Co{sup 2+/3+}, Ni{sup 2+}) by the means of Time-dependent Density Functional Theory (TD-DFT) and Ligand Field Density Functional Theory (LF-DFT). Influence of various exchange-correlation (XC) approximations have been studied, and results have been compared to the experimental transition energies, as well as, to the previous high-level ab initio calculations. TD-DFT gives satisfactory results in the cases of d{sup 2}, d{sup 4}, and low-spin d{sup 6} complexes, but fails in the cases when transitions depend only on the ligand field splitting, and for states with strong character of double excitation. LF-DFT, as a non-empirical approach to the ligand field theory, takes into account in a balanced way both dynamic and non-dynamic correlation effects and hence accurately describes the multiplets of transition metal complexes, even in difficult cases such as sextet-quartet splitting in d{sup 5} complexes. Use of the XC functionals designed for the accurate description of the spin-state splitting, e.g., OPBE, OPBE0, or SSB-D, is found to be crucial for propermore » prediction of the spin-forbidden excitations by LF-DFT. It is shown that LF-DFT is a valuable alternative to both TD-DFT and ab initio methods.« less
Authors:
 [1] ; ;  [2] ;  [3]
  1. Innovation center of the Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Republic of Serbia (Serbia)
  2. Department of Chemistry, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Republic of Serbia (Serbia)
  3. Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Republic of Serbia (Serbia)
Publication Date:
OSTI Identifier:
22415927
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 21; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHROMIUM IONS; COBALT COMPLEXES; COBALT IONS; COMPARATIVE EVALUATIONS; CORRELATIONS; DENSITY FUNCTIONAL METHOD; EXCITATION; FIELD THEORIES; IRON IONS; LIGANDS; MANGANESE IONS; MULTIPLETS; NICKEL COMPLEXES; NICKEL IONS; NITROGEN IONS; SPIN; TIME DEPENDENCE; WATER