Molecular dynamics simulations of the condensation coefficient of water

Experiments have found the condensation coefficient for water condensing onto pure water to be between 1 and 0.01. This wide variation persists even in the more recent experiments in which values of about 1, 0.77 ± 0.06, and 0.2 ± 0.1 have been reported. However, current molecular dynamics simulations of water consistently result in a condensation coefficient of about 1. These water models may overestimate the condensation coefficient by assigning condensed phase parameters to the bulk, surface, and gas phase water molecules in the simulations. We varied the dipole moment and the Lennard-Jones parameters for a gas phase water molecule in a condensation simulation using the SPC/E model. With modest changes to the dipole moment and the Lennard-Jones parameters, we have obtained a value of 0.77. However, we have concluded that to obtain a simulation condensation coefficient of 0.2, unrealistic parameters must be assigned to the water molecules.