In this paper, we have extended to the calculation of hyperfine coupling constants, the model recently proposed by some of the present authors [Giovannini et al., J. Chem. Theory Comput. 13, 4854-4870 (2017)] to include Pauli repulsion and dispersion effects in Quantum Mechanical/Molecular Mechanics (QM/MM) approaches. The peculiarity of the proposed approach stands in the fact that repulsion/dispersion contributions are explicitly introduced in the QM Hamiltonian. Therefore, such terms not only enter the evaluation of energetic properties but also propagate to molecular properties and spectra. A novel parametrization of the electrostatic fluctuating charge force field has been developed, thus allowing a quantitative reproduction of reference QM interaction energies. Such a parametrization has been then tested against the prediction of EPR parameters of prototypical nitroxide radicals in aqueous solutions.

Effective yet reliable computation of hyperfine coupling constants in solution by a QM/MM approach: Interplay between electrostatics and non-electrostatic effects

Giovannini, Tommaso;Lafiosca, Piero;Chandramouli, Balasubramanian;Barone, Vincenzo;Cappelli, Chiara
2019

Abstract

In this paper, we have extended to the calculation of hyperfine coupling constants, the model recently proposed by some of the present authors [Giovannini et al., J. Chem. Theory Comput. 13, 4854-4870 (2017)] to include Pauli repulsion and dispersion effects in Quantum Mechanical/Molecular Mechanics (QM/MM) approaches. The peculiarity of the proposed approach stands in the fact that repulsion/dispersion contributions are explicitly introduced in the QM Hamiltonian. Therefore, such terms not only enter the evaluation of energetic properties but also propagate to molecular properties and spectra. A novel parametrization of the electrostatic fluctuating charge force field has been developed, thus allowing a quantitative reproduction of reference QM interaction energies. Such a parametrization has been then tested against the prediction of EPR parameters of prototypical nitroxide radicals in aqueous solutions.
2019
Physics and Astronomy (all); Physical and Theoretical Chemistry
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/78547
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