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 orbita l/local origin (LORG) method are presented. The accuracy of the AATs o btained from this method is compared to the accuracy obtained in calcu lations using the common origin (GO) method, the distributed origin (D O) method, and the London method for four small molecules, at two basi s set levels (VD/3P and DZ/POL). LORG and DO AATs are of comparable ac curacy. The LORG method enables AATs to be broken down into contributi ons from individual localized orbitals, and this is illustrated in a c alculation on formic acid, for which we also present a localized orbit al decomposition of the atomic polar tensors (APTs). The same calculat ion is used to detail the local contributions to the AATs, which are o mitted in the approximate localized molecular orbital (LMO) model.