Quantum densities of states of fluxional polyatomic systems from a superposition approximation.
The superposition method is used to calculate quantum densities of states of polyatomic systems with multiple isomeric structures. For each isomer, anharmonicities are included rigorously using a Dunham expansion of the vibrational energy levels and short exchange Monte Carlo simulations are used to compute the individual quantum densities of states. The method is applied to the computation of thermodynamical properties of the Ar(13) and Ne(13) clusters. The canonical heat capacities are found in very satisfactory agreement with the predictions of quantum or semiclassical sampling methods.
Calvo
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LASIM, Université de Lyon and CNRS UMR 5579, F69622 Villeurbanne Cedex, France.
Parneix
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Basire
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