Development of a Flexible‐Monomer Two‐Body Carbon Dioxide Potential and Its Application to Clusters up to (CO2)13

• Published in: Journal of computational chemistry Vol. 38; no. 32; pp. 2763 - 2774
• Main Authors: Sode, Olaseni, Cherry, Jasmine N.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 15.12.2017
• Subjects: Carbon dioxide; Clusters; coupled cluster; Dimers; electronic structure; Isomers; Monomers; polynomial fitting; Potential energy; potential energy surface; carbon dioxide; coupled cluster; polynomial fitting; potential energy surface; electronic structure
• ISSN: 0192-8651; 1096-987X
• DOI: 10.1002/jcc.25053

A flexible‐monomer two‐body potential energy function was developed that approaches the high level CCSD(T)/CBS potential energy surface (PES) of carbon dioxide (CO2) systems. This function was generated by fitting the electronic energies of unique CO2 monomers and dimers to permutationally invariant polynomials. More than 200,000 CO2 configurations were used to train the potential function. Comparisons of the PESs of six orientations of flexible CO2 dimers were evaluated to demonstrate the accuracy of the potential. Furthermore, the potential function was used to determine the minimum energy structures of CO2 clusters containing as many as 13 molecules. For isomers of (CO2)3, the potential demonstrated energetic agreement with the M06‐2X functional and structural agreement of the B2PLYP‐D functional at substantially reduced computational costs. A separate function, fit to MP2/aug‐cc‐pVDZ reference energies, was developed to directly compare the two‐body potential to the ab initio MP2 level of theory. © 2017 Wiley Periodicals, Inc. A two‐body potential energy function with flexible monomers fit to CCSD(T)‐F12b/aug‐cc‐pVTZ energies is developed and described. The function is applied to the optimization of clusters of CO2 molecules, where it is shown to accurately reproduce the dimer potential energy surface and predict the most stable structures for larger clusters.