Novel Method for Geometry Optimization of Molecular Clusters:  Application to Benzene Clusters

Abstract

A heuristic and unbiased method for searching optimal geometries of clusters of nonspherical molecules was constructed from the algorithm recently proposed for Lennard-Jones atomic clusters. In the method, global minima are searched by using three operators, interior, surface, and orientation operators. The first operator gives a perturbation on a cluster configuration by moving molecules near the center of mass of a cluster, and the second one modifies a cluster configuration by moving molecules to the most stable positions on the surface of a cluster. The moved molecules are selected by employing a contribution of the molecules to the potential energy of a cluster. The third operator randomly changes the orientations of all molecules. The proposed method was applied to benzene clusters. It was possible to find new global minima for (C6H6)11, (C6H6)14, and (C6H6)15. Global minima for (C6H6)16 to (C6H6)30 are first reported in this article.

Binary Lennard-Jones atomic clusters: Structural features induced by large-sized atoms

“…The method optimizes cluster geometries with two types of geometrical perturbations and yielded the global minima of LJ clusters with 10 to 561 atoms reported previously and the new minima for 6 LJ clusters. Then the method is improved to apply it to complicated clusters, molecular homoclusters where molecular orientations are further required as optimized parameters [11,12]. The first purpose of the present study is to improve the above optimization method for application to another type of complicated clusters, atomic heteroclusters.…”

Theoretical investigation on structural properties of ethylene clusters (C2H4)n (n⩽25)

“…3). The non-icosahedral geometry is first observed for van der Waals homoclusters consisting of thirteen molecules; the clusters previously investigated (benzene [1], carbon dioxide [3], acetylene [4], ethane [2], and molecular nitrogen [16] clusters) take icosahedrons. This can be explained using the deviation of the tetramer geometry from a regular tetrahedron.…”

“…Previously the present author proposed a geometry optimization method for molecular clusters (the Heuristic Method combined with Geometrical Perturbations, HMGP) [1,2]. The method was applied to carbon dioxide clusters (CO 2 ) n (n ≤ 40) [3] and acetylene clusters (C 2 H 2 ) n (n ≤ 55) [4].…”

Exploring energy landscapes: from molecular to mesoscopic systems

“…77 The majority of computational studies of water and benzene clusters focus on identifying low-lying minima on the potential energy surface. 77,[83][84][85][86][87][88][89][90][91][92] In fact, benzene clusters are often studied to benchmark new global optimisation techniques. 87,88,91,93 Because of the fundamental interest in understanding the interaction of water with aromatic systems, 94 small water clusters complexed to a single benzene molecule have also been studied.…”