Abstract
π-π* Transition energies of steroid polyenes were calculated by the Pariser-Parr-Pople type LCAO-MO-CI method. Excellent coincidence was obtained between the calculated and the observed energies. The method was applied to the calculation of π-π* transition energies of steroid polyenyl cations having the structures assumed in the previous paper. Calculated energies of most of the cations were found to coincide very well with the wavelengths of maxima in the absorption spectra of steroid polyenes in strong acids. This result supports the validity of the assumptions made in the previous paper. The method was not suitable for the calculation of π-π* transition energies of steroid polyenyl cations having π electrons delocalized on more than nine carbon atoms.
