Finding the Pattern in the Space of ab initio and DFT Theoretical Descriptions: A Pattern Recognition and Metric Space Approach Based on the Electric Response Properties of the Open and Ring Isomers of XO2 (X = O,S)

• Published in: Computational Methods in Science and Engineering: Advances in Computational Science Volume 1 (AIP Conference Proceedings Series Volume 1108) 2009-01, Vol.1108, p.215-226
• Main Author: Xenides, Demetrios
• Format: Article
• Language: English
• ISSN: 0094-243X
• DOI: 10.1063/1.3117133

A test set of four molecules was formed by considering the bonding in the open (C2v) and ring (D3h) forms of ozone, and the open and ring isomers of sulfur dioxide (both of C2v symmetry). This test set was used as to assess the performance of various Density Functional Theory (DFT) methods in (hyper)polarizability calculations against well established ab initio methods. The analysis is aided by arguments chosen from the information theory, graph theory and pattern recognition fields of Mathematics: The multidimensional space is formed by the methods which are playing the role of vectors with the independent components of the electric properties to act as the coordinates of these vectors, hence the relation between different vectors (e.g., methods) can be quantified by a proximity measure. Results are in agreement with previous studies revealing the acceptable and consistent behavior of the mPW1PW91, B3P86 and PBE1PBE methods. We note the remarkable good performance of the B2PLYP and mPW2PLYP functionals which are for the first time used in calculations of electric responce properties.