Dioxygen spectra and bioactivation

Authors

  • Boris F. Minaev,

    1. Department of Natural Sciences, Bogdan Hmelnitsky National University, Cherkassy, Ukraine
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  • N. Arul Murugan,

    1. Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, Stockholm, Sweden
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  • Hans Ågren

    Corresponding author
    1. Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, Stockholm, Sweden
    • Department of Natural Sciences, Bogdan Hmelnitsky National University, Cherkassy, Ukraine
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Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, SE-10691, Stockholm, Sweden. E-mail: agren@theochem.kth.se

Abstract

Intensities of spin-forbidden transitions in electronic absorption and emission spectra of molecular oxygen are analyzed in order to understand the key mechanisms of spin-states mixing induced by spin-orbit coupling (SOC) and the ways to overcome spin prohibition for various photophysical and biochemical processes. Multireference configuration interaction calculations with SOC account are used to generalize spin-selection rules for the oxygen atmospheric and Herzberg bands in free O2 molecule and in collision complexes. Intensity enhancement of the atmospheric a1ΔgX3Σg, b1Σg+X3Σg, and Noxon b1Σg+a1Δg transitions upon bimolecular collisions are compared with those for Herzberg III transitions A′3ΔuX3Σg. Electric quadrupole, dipole, and magnetic approximations are used for transition probability calculations. Intensity distribution in rotational lines is also considered. With this background, we propose some simple spin-selection rules for dioxygen activation in enzymatic reactions. © 2013 Wiley Periodicals, Inc.

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