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International Journal of Modern Physics C

ACCURATE ROVIBRATIONAL STATE ENERGIES OF BOSONIC VAN DER WAAL DIMERS

Mervlyn Moodley

Published May 13, 2013• 0 citations
Publisher

Abstract

Over the past few decades many new and improved techniques have been developed to calculate ground and excited states of atomic clusters with varying degrees of accuracy. Together with progressively enhanced computer capabilities and the development of sophisticated techniques, the accuracy of results obtained from ab initio methods are closely approximating machine precision. In this paper, we use the finite difference method, whose precision is only governed by the machine precision, together with an optimization criterion to calculate the spectrum of two-body van der Waal clusters. This method is also shown to be robust enough to calculate energies close to the unbinding transition.

DOI
10.1142/s0129183113500575

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The computational physics methods of various processes have become very popular during the last several years. Our interest in his field is predominantly motivated by the expectation that it will be possible to perform a detailed comparison between experimental and theoretical results obtained in the study of clusters of a variety of sizes. Algebraic invariants are employed to deal efficiently with the many-body correlations. We study the applicability of the developed trial wave functions over some range of particle masses, from Ar to He and lighter. We compute the ground and excited states energies and various geometric sizes of small clusters as a function of a continuously varied mass parameter. For sufficiently small masses the cluster can no longer support a bound state, and we are interested in particular in the behavior of the clusters in the vicinity of the critical mass, i.e., the point at which the binding energy approaches zero. We show that the use of bosonic polynomials provides enough variational freedom to approximate ground and excited states of clusters of any mass. We discuss how the properties of clusters change with mass.