A HYBRID DENSITY-FUNCTIONAL CLASSICAL MOLECULAR-DYNAMICS SIMULATION OF A WATER MOLECULE IN LIQUID WATER

A hybrid NVE Molecular Dynamics simulation of liquid water is presente d using a coupled Density Functional/Molecular Mechanics hamiltonian. The quantum subsystem is a single water molecule described by means of a triple-zeta quality basis set with polarization orbitals on oxygen and hydrogen atoms. Non-local exchange-correlation corrections are inc luded self-consistently. The classical system is constituted by 128 TI P3P water molecules. Results are in reasonable agreement with experime ntal data and in particular a good description of the solute polarizat ion is obtained. Large fluctuations of the instantaneous value of the dipole moment of the quantum molecule are predicted.