A comparative study of SCFMO calculations on alternant and nonalternant hydrocarbons

Excimer model for fluorene and dibenzofuran

“…Carbon valence-state ionization potentials and one-center repulsion integrals for naphthalene were taken from the literature;24 the corresponding values for fluorene and dibenzofuran were taken to be the same as those for phenanthrene. 26 For the etheroxygen ionization potential and one-center integrals we used 33.9 and 16.2 eV, respectively. 28 The SCF ground-state wave functions were allowed to interact with the lowest six excited-state configurations.…”

Polarization spectra in stretched polymer sheets. II. Separation of .pi.-.pi.* absorption of symmetrical molecules into components

“…If K-1 exists, A = K_1 E, where Thus, the solutions are A. '(X) = Al(\)-(K1Ki -K2K3)/K4 = E\ ( ) -d{l°Ex(\) (5) /( ) = ,( )•( 4 -, ^/ , = Ex{\) -dx*En{\)…”

Accurate heats of atomization and accurate bond lengths.: I. Benzenoid hydrocarbons

“…(Pople-Pariser-Parr -self-consistent field -molecular orbital) theory of pi electron systems (1,2) has been successfully applied to the prediction of transition energies (2,3), comparatively little work has been done either in the realm of chemical reactivity or on ground state properties of conjugated systems. Traditionally, complete sigma and pi separation has been assumed, and the sigma electrons have been treated as if data permit the empirical calculation of the heats of atomization (AH,).…”

“…It is difficult t o find one general set that can predict all chemical properties. Many of these semi-empirical parameters, such as the resonance integral (Pij) and the two center repulsion inlegral (yij), depend arbitrarily on a convenient function form (3,6) rather than on a sound theoretical basis. Therefore a comparative study of the different parameters has been carried out, and both the pi and sigma bond energies have been considered simultaneously on a variable geometry basis.…”