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The thermodynamic and structural properties of (NH4Cl)n clusters, n =3 – 10 are studied. Using the method of simulated annealing, the geometries of several isomers for each cluster size are examined. Jump-walking Monte Carlo simulations are then used to compute the constant-volume heat capacity for each cluster size over a wide temperature range. To carry out these simulations a new parallel algorithm is developed using the parallel virtual machine (PVM) software package. Features of the cluster potential energy surfaces, such as energy differences among isomers and rotational barriers of the ammonium ions, are found to play important roles in determining the shape of the heat capacity curves.

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© 1996 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Matro, Alexander, David L. Freeman and Robert Q. Topper. ʺComputational Study of the Structures and Thermodynamic Properties of Amonium Chloride Clusters Using a Parallel Jump-Walking Approach.ʺ Journal of Chemical Physics. 104(21):8690-8702. June 1996.and may be found at