Ab-initio calculation, using ab-initio pseudopotentials, of some electronic properties of ethane, methylsilane and disilane

Recently-developed ab-initio pseudopotentials are employed for the calculation of electronic energy levels and internal rotation barriers in C₂H₆, CH₃SiH₃ and Si₂H₆. The calculations are performed at the experimental internal geometry, using double-zeta quality gaussian basis sets. The results show that the errors caused by the use of the pseudo-potential are negligible compared to those of limited basis-set size, so that the pseudopotentials can indeed be used to replace the core electrons.