Use of nonrelativistic wavefunctions for the prediction of properties of molecules containing atoms of high Z. PbO as a test case

Using a minimum basis set of Slater functions, nonrelativistic self-consistent-field calculations have been carried out for the lead monoxide molecule. The purpose of the calculations was to provide an indirect test of the importance of relativistic effects in molecules containing atoms with atomic number as high as 82. The predicted spectroscopic constants of pbO are in about as good agreement with experiment as were the results from comparable calculations on the obviously nonrelativistic molecule CO. The electronic structures of the two molecules are briefly compared in terms of Mulliken population analyses.