<span style="mso-ansi-language:EN-US" lang="EN-US">Electrostatics and tailoring for aggregation of small linear molecules: An <i style="mso-bidi-font-style:normal">ab initio</i> study </span>

Abstract

<span style="mso-ansi-language:EN-US" lang="EN-US">Features of the molecular electrostatic potential (MESP) for three linear triatomic molecules, <span style="mso-bidi-font-style:italic">viz., CO₂, CS₂ and OCS are utilized for a comparative study of their aggregation into small clusters. Trial structures of clusters upto tetramers, generated by using the MESP insights, are subjected to geometry optimization employing second-order Møller-Plesset (MP2)theory, with correlation consistent aug-cc-pvTZ (aTZ) basis set. Single point energies at MP2/aQZ levels are calculated for the estimation of binding energies at complete basis set (CBS) limit. Calculations at the coupled cluster singles and doubles with perturbative triples (CCSD(T)) level are also reported for the most favorable tetramers using the molecular tailoring approach (MTA). Geometrical parameters such as rotational constants thus obtained are found to be in good agreement with the corresponding experimental ones. Minimal nature of the reported structures is confirmed by the vibrational frequency calculations at MP2/aDZ level of theory. The current work offers some hints towards the patterns in the oligomer formation for these molecules and a comparison of the motifs found in the corresponding crystal structure is made.

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