One-electron pseudo-potential investigation of NO(X2Π)–Arn clusters (n = 1,2,3,4)

Abstract

In this work, we investigate the minimal energy and low-lying isomers of the ground state of NOArn clusters using a hybrid pseudo-potential model, where a single electron quantum description is combined with the classical argon–argon pair potential and an expansion in terms of the Legendre polynomials. In such model, we use two centres of polarisation for NO+, where we considered for each nuclear configuration an analytic dipole polarisation for N+ and O+. The reliability of our model is checkedby comparison of the NO(X2Π)–Ar potential energy surfacewith that deduced using the multireference configuration interaction (MRCI+Q) approach. The results of this formalism agree quite well with the MRCI ones over a wide range of nuclear arrangements. To determine the lowest-energy isomers of the NOArn clusters, we use the so-called basin hopping method of Wales et al. which combines a Monte-Carlo exploration and deformation method. We found that the NOArn (n = 1–4) clusters are structurally very similar to the homogenous rare gas clusters Arn+1, where NO replaces a surface argon atom. The obtained structures are in agreement with those obtained using the diatomics-in-molecules calculations, evidencing the efficiency of the pseudo-potential model proposed here.