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 إ 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.