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Ab initio multireference singles and doubles configuration interaction study of the low‐energy states of iron mononitride
Author(s) -
de Oliveira Marcos Herrerias,
Martins Filho Harley Paiva,
Da Motta Neto Joaquim Delphino
Publication year - 2011
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.22685
Subject(s) - complete active space , configuration interaction , multireference configuration interaction , ab initio , wave function , chemistry , atomic physics , potential energy , ground state , ab initio quantum chemistry methods , computational chemistry , physics , excited state , density functional theory , basis set , molecule , organic chemistry
Low‐lying states of iron mononitride are studied using ab initio multireference singles and doubles configuration interaction (MR‐SDCI) calculations. For each one of the 2 Δ, 4 Π, 6 Σ + , 2 Π, 4 Δ, 6 Π, and 6 Δ states the reference wavefunction has been obtained at the complete active space self consistent field (CASSCF) level and relativistic corrections were included. Potential energy curves are presented for all states. Spectroscopic constants have been determined for the 2 Δ, 4 Π, and 6 Σ + states assuming a Morse‐type potential function using a code written by one of us. For the 2 Δ state, the calculated spectroscopic constants are R e = 1.567 Å, ω e = 827 cm −1 , and μ = 1.68 D. Rotovibrational analysis suggests that the third vibrational level of the 2 Δ state already surpasses the first vibrational levels of the 4 Π and 6 Σ + states, what reassures the difficulty in correctly attributing the lines of the experimental spectrum. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010