Search

In this work, the GLOB model, an effective and reliable computational approach well suited for ab initio and QM/MM molecular dynamics simulations of complex molecular systems in solution, has been applied to study two representative open-shell systems, the cobalt(II) ion and the glycine radical in aqueous solution, with special reference to their structural and magnetic properties. The main structural features of the solvent cage around the cobalt ion and the hydrogen bonding patterns around the neutral and zwitterionic forms of the glycine radical have been investigated in some detail. The general good agreement with experiments supports the use of the present model to investigate more challenging and biological/technological relevant open-shell systems.

The characterization of fundamental vibrational levels from the analysis of ab-initio dynamics is discussed. Results from test calculations are compared with those obtained by a second-order perturbative procedure to include anharmonicity exploiting the same ab-initio potential. The influence of the single molecular modes on vibrationally averaged properties calculated on the fly during the dynamics is also analyzed. Formaldehyde, both in the gas phase and in acetonitrile solution, and the vinyl radical in the gas phase have been chosen as test molecules, while the hyperfine coupling constants of the open shell system is computed as an example of molecular properties. Results allow for a quantitative comparison with experimental data.