QUANTITATIVE PREDICTION OF ABSORPTION MAXIMA IN THE ELECTRONIC-SPECTRA OF UNSATURATED-COMPOUNDS - EXTRAPOLATION FROM FRAGMENTS TO MOLECULESIN QUANTUM-CHEMICAL CALCULATIONS

The possibility of quantitative prediction of maxima in the electronic absorption spectra of unsaturated organic compounds is studied by the Pariser-Parr-Pople method with fitted parameters. The quantum chemica l methods are classified according to the type of extrapolation:from e lementary particles (physical constants) to molecules, from atoms to m olecules, and from fragments to molecules.