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A model electronic Hamiltonian to describe low‐lying d–d and metal‐to‐ligand charge‐transfer excited states of [Fe(bpy) 3 ] 2+
Author(s) -
Iuchi Satoru,
Koga Nobuaki
Publication year - 2021
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.26444
Subject(s) - hamiltonian (control theory) , excited state , wave function , electronic structure , singlet state , ab initio , atomic physics , chemistry , density functional theory , physics , configuration interaction , hamiltonian matrix , molecular physics , quantum mechanics , computational chemistry , eigenvalues and eigenvectors , mathematical optimization , mathematics , symmetric matrix
Abstract A simple practical method to compute both d–d and metal‐to‐ligand charge‐transfer (MLCT) excited states of iron(II) polypyridyl complexes is proposed for use in simulation studies. Specifically, a model electronic Hamiltonian developed previously for d–d excited states of [Fe(bpy) 3 ] 2+ is extended to deal with low‐lying MLCT excited states simultaneously by including the MLCT electronic configurations into the basis functions of the model Hamiltonian. As a first attempt, parameters in the model Hamiltonian matrix elements are determined by using density functional theory (DFT) and time‐dependent (TD‐)DFT calculation results as benchmarks. To examine the performance of the model Hamiltonian, the potential energy curves along the interpolation between the lowest singlet and quintet state structures are compared to those from the (TD‐)DFT calculations and to those from CASPT2 calculations in literature. The electronic absorption spectrum computed through molecular dynamics simulation is compared to the experimental spectrum. The spin‐orbit couplings at the ground state structure are also compared to those from wavefunction‐based ab initio electronic structure calculations. The results indicate that the constructed model Hamiltonian provides reasonable information on both the low‐lying d–d and MLCT excited states of [Fe(bpy) 3 ] 2+ .