Self-consistent wave functions of conjugated molecules by the one-dimensional electron gas model: Application to geometries and absorption spectra

A model based on one-dimensional electron gas theory has been developed which improves the π-electron wave functions of conjugated molecules by taking changes of bond length differences into account. Experimental bond lengths are reproduced with an average deviation of 0·005 Å; excitation energies are markedly improved over the simple model. The reliability of the model with respect to geometries is comparable to the PPP-SCF method.