Comment on ‘Theoretical study on PbS, PbO and their anions’ [Chem. Phys. Lett. 370 (2003) 39]

A recent report by Wu [Chem. Phys. Lett. 370 (2003) 39] compared the calculated re, ωe, and De values of PbO, PbS, PbO−, and PbS− with experimental data. Various DFT and ab initio MP2 and QCISD methods were employed together with a large-core RECP for Pb and small-size basis sets. In this comment, we calculate the spectroscopic constants of PbO using a small-core RECP and large valence basis sets in order to meaningfully assess the performance of the methods. For PbO, spin–orbit effects should also be considered when comparing such scalar-relativistic results with experimental data.