Molecular dynamics of hydrogen peroxide in liquid water using a combined quantum/classical force field

Abstract

Molecular dynamics simulations using a combined quantum/classical force field have been carried out to investigate the properties of hydrogen peroxide in aqueous solution. Radial distribution functions exhibit close similarities with those obtained for the OH radical. They show that H 2O 2 is a better proton donor than H 2O but a weaker proton acceptor. Solvent effects modify the O–H bonds, which are weakened and elongated by 0.02 Å. The HOOH dihedral angle decreases by 11° and the dipole moment increases by 0.8 D. The O–O bond length and bond order do not change much. Fluctuations of the frontier orbital energies are analyzed in detail as a function of both, the HOOH geometry and the solvent configuration. Hydrogen-bonds with solvent molecules appear to have an opposite influence depending on their donor/acceptor character. Interconversion between energy minima always proceeds through a transoid transition state.