AB-INITIO CALCULATIONS OF ATOMIC POLAR AND AXIAL TENSORS USING THE LOCALIZED ORBITAL LOCAL ORIGIN (LORG) APPROACH

Calculations of atomic axial tensors (AATs) using the localized orbital/local origin (LORG) method are presented. The accuracy of the AATs obtained from this method is compared to the accuracy obtained in calculations using the common origin (GO) method, the distributed origin (DO) method, and the London method for four small molecules, at two basis set levels (VD/3P and DZ/POL). LORG and DO AATs are of comparable accuracy. The LORG method enables AATs to be broken down into contributions from individual localized orbitals, and this is illustrated in a calculation on formic acid, for which we also present a localized orbital decomposition of the atomic polar tensors (APTs). The same calculation is used to detail the local contributions to the AATs, which are omitted in the approximate localized molecular orbital (LMO) model.