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

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 checked by comparison of the NO(X-2 Pi)-Ar potential energy surface with 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. [GRAPHICS] .