Understanding Packing Patterns in Crystals by Analysis of Small Aggregates: A Case Study of CS₂

Abstract

The molecular electrostatic potential (MESP) of the CS2 molecule, in conjunction with the cluster building algorithm, is utilized for generating trial geometries of medium-sized (CS2)n (n = 5-8) aggregates. MESP features suggest crossed, parallel stacked, T-shaped and L-shaped geometries for CS2 clusters. These initial geometries are subjected to geometry optimization employing second-order Møller-Plesset (MP2) theory, with correlation consistent aug-cc-pvDZ (aDZ) basis set. Single-point energies at MP2/aTZ levels are calculated for the estimation of binding energies at complete basis set (CBS) limit. The minimal nature of the reported structures is confirmed by doing vibrational frequency run at MP2/aDZ level of theory using the molecular tailoring approach (MTA). The two- and three-body interaction energies are computed for clusters with n = 5, 6, and 7 and these are suggestive of change in contact patterns with increasing n. Such an analysis is found to offer a qualitative explanation of the packing pattern found in the crystal structure.

Halogen Bonding: A Halogen-Centered Noncovalent Interaction Yet to Be Understood

“…The carbon quadrupole moment is negative, reflecting a reduced π-electron density around the C atom [196]. Because of this nature of the molecule, Singh et al [281] found that the molecule displays versatile coordination modes, and has ability to feature crossed, parallel-stacked, T-shaped, and L-shaped geometries in its clusters. This ability of the molecule explains why CS 2 could displays a number of coordination modes to form the hexabromofullerene carbon disulfide crystal.…”

Electron diffraction as a structure tool for charged and neutral nanoclusters formed in superfluid helium droplets

“…The dimer forms a cross with a D 2d symmetry, 74 the trimer forms a pinwheel with a D 3 symmetry, 75 and the tetramer forms a barrel with a D 2d symmetry, 76 in general agreement with theoretical calculations. 77,78 Clusters containing more than 4 monomers are predicted to converge to the crystal structure, 79 orthorhombic 80 containing CS 2 pairs. The diffraction profile of small CS 2 clusters formed in superfluid helium droplets is shown in Fig.…”