Monte Carlo studies of hydrogen fluoride clusters: Cluster size distributions in hydrogen fluoride vapor

Abstract

An investigation into the structure and composition of hydrogen fluoride vapor is reported. Calculations are performed using a modified central force model potential developed by Klein and McDonald. Using a simulated annealing procedure, minimum energy structures for HF clusters are investigated ranging in size from n=2 to 7. Good agreement is found for the structural parameters obtained from the model potential and other theoretical and experimental information. The Monte Carlo method is used to determine the thermodynamic energy, entropy, and Gibbs free energy of the hydrogen fluoride clusters at 1 atm pressure and 100 and 273 K. A minimum in the Gibbs free energy change is found at n=4 implying that tetramers are very important in the vapor.