CNDO Calculation of Dipole-Moment Derivatives and Infrared Intensities of BF3

Abstract

Dipole‐moment derivatives, ∂p/∂Sj, have been calculated (according to the method of Segal and Klein) for the infrared‐active symmetry species of BF3, using approximate wavefunctions from the CNDO/2 procedure of Pople and Segal. The results agree fairly closely with the experimental values determined by McKean. In an attempt to understand the calculated ∂ p/∂ S j values more fully, we have analyzed them in terms of derivatives (∂ μ/∂ r k ) with respect to the generalized internal coordinates, rk . The latter calculated derivatives have been further analyzed in order to deduce the magnitudes of the different factors contributing to the values of ∂ μ/∂ r k . Comparison is made with corresponding values from the related F2CO molecule.