Accommodation coefficients for water vapor at the air/water interface

The accommodation of water vapor at the air/water interface is studied using classical molecular dynamics computer simulations. From 250 initial conditions of a gas phase water molecule approaching the surface of liquid water with a thermal impact velocity, the thermal and mass accommodation coefficients are determined to be 1.0 and 0.99, respectively, at 300 K. When the approaching water molecule is 5 A above the liquid, it is accelerated towards the surface, which is followed by a slight rotational excitation upon impact. Within 4 ps of striking the surface, the total kinetic energy is equilibrated and the equilibrium number of water molecules in the first and second solvent shells is obtained. (C) 2004 Elsevier B.V. All rights reserved.