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Multiconfigurational Effects in Theoretical Resonance Raman Spectra
Author(s) -
Ma Yingjin,
Knecht Stefan,
Reiher Markus
Publication year - 2017
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201601072
Subject(s) - density matrix renormalization group , chemistry , valence bond theory , complete active space , atomic orbital , raman spectroscopy , excited state , resonance (particle physics) , molecular physics , electronic structure , molecular orbital , density functional theory , atomic physics , computational chemistry , physics , electron , quantum mechanics , renormalization group , molecule , organic chemistry , basis set
We analyze resonance Raman spectra of the nucleobase uracil in the short‐time approximation calculated with multiconfigurational methods. We discuss the importance of static electron correlation by means of density‐matrix renormalization group self‐consistent field (DMRG‐SCF) calculations. Our DMRG‐SCF results reveal that a minimal active orbital space that leads to a qualitatively correct description of the resonance Raman spectrum of uracil should encompass parts of the σ/σ* bonding/anti‐bonding orbitals of the pyrimidine ring. We trace these findings back to the considerable entanglement between the σ/σ* bonding/anti‐bonding as well as valence π/π* orbitals in the excited‐state electronic structure of uracil, which indicates non‐negligible non‐dynamical correlation effects that are less pronounced in the electronic ground state.