Molecular dynamics investigation of benzene in supercritical water

Microscopic structure and diffusion properties of benzene in ambient water (298 K, 0.1 MPa) and supercritical water (673-773 K, 25-35 MPa) are investi gated by molecular dynamics simulation with site-site models. it is found t hat at the ambient condition, the water molecules surrounding a benzene mol ecule form a hydrogen bond network. The hydrogen bond interaction between s upercritical water molecules decreases dramatically under supercritical con ditions. The diffusion coefficients of both the solute molecule and solvent molecule at supercritical conditions increase by 30-180 times than those a t the ambient condition. With the temperature approaching the critical temp erature, the change of diffusion coefficient with pressure becomes pronounc ed.