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Spectroscopic Properties of Lumiflavin: A Quantum Chemical Study
Author(s) -
Kar Rajiv Kumar,
Borin Veniamin A.,
Ding Yonghong,
Matysik Jörg,
Schapiro Igor
Publication year - 2018
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.13023
Subject(s) - excited state , chemistry , singlet state , anharmonicity , solvatochromism , triplet state , resonance (particle physics) , molecular physics , excitation , solvent effects , density functional theory , atomic physics , computational chemistry , molecule , solvent , physics , organic chemistry , quantum mechanics
In this work, the electronic structure and spectroscopic properties of lumiflavin are calculated using various quantum chemical methods. The excitation energies for ten singlet and triplet states as well as the analysis of the electron density difference are assessed using various wave function‐based methods and density functionals. The relative order of singlet and triplet excited states is established on the basis of the coupled cluster method CC 2. We find that at least seven singlet excited states are required to assign all peaks in the UV /Vis spectrum. In addition, we have studied the solvatochromic effect on the excitation energies and found differential effects except for the first bright excited state. Vibrational frequencies as well as IR , Raman and resonance Raman intensities are simulated and compared to their experimental counterparts. We have assigned peaks, assessed the effect of anharmonicity, and confirmed the previous assignments in case of the most intense transitions. Finally, we have studied the NMR shieldings and established the effect of the solvent polarity. The present study provides data for lumiflavin in the gas phase and in implicit solvent model that can be used as a reference for the protein‐embedded flavin simulations and assignment of experimental spectra.