NONLINEAR-OPTICAL PROPERTIES OF ORGANIC-MOLECULES .14. CALCULATIONS OF THE STRUCTURE, ELECTRONIC-PROPERTIES AND HYPERPOLARIZABILITIES OF CYCLOPENTADIENYLPYRIDINES

The structures of a series of cyclopentadienylpyridines have been calc ulated using the AM1 method and reasonable correlations have been foun d with crystallographic data where available. Subsequent calculations have been carried out on these structures using the CNDOVSB method to obtain dipole moments, transition energies and hyperpolarisabilities. The two methods are found to give widely different values for the grou nd-state dipole moments. The calculated hyperpolarisabilities suggest that these molecules have considerably superior non-linear optical pro perties to conventional donor-acceptor aromatics.