title: Extension of the AMBER Force Field for Nitroxide Radicals and Combined QM/MM/PCM Approach to the Accurate Determination of EPR Parameters of DMPO-H in Solution.
abstract: A computational strategy that combines both time-dependent and time-independent approaches is exploited to accurately model molecular dynamics and solvent effects on the isotropic hyperfine coupling constants of the DMPO-H nitroxide. Our recent general force field for nitroxides derived from AMBER ff99SB is further extended to systems involving hydrogen atoms in β-positions with respect to NO-moiety. The resulting force-field has been employed in a series of classical molecular dynamics simulations, comparing the computed EPR parameters from selected molecular configurations to the corresponding experimental data in different solvents. The effect of vibrational averaging on the spectroscopic parameters is also taken into account, by second-order vibrational perturbation theory involving semidiagonal third energy derivatives together first and second property derivatives.
authors.affiliation: Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid , 28049 Madrid, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Hermosilla
authors.affiliation: Istituto per i Processi Chimico-Fisici , Consiglio Nazionale delle Ricerche, Area della Ricerca, via Moruzzi 1, I-56124 Pisa, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Prampolini
authors.affiliation: Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid , 28049 Madrid, Spain.
authors.forename: Paloma
authors.initials: P
authors.lastname: Calle
authors.affiliation: Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid , 28049 Madrid, Spain.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: García de la Vega
authors.affiliation: Scuola Normale Superiore , Piazza dei Cavalieri 7, I-56126 Pisa, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Brancato
authors.affiliation: Scuola Normale Superiore , Piazza dei Cavalieri 7, I-56126 Pisa, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barone