The Study of Annelation Series of Benzenoid Hydrocarbons. I. The Influence of Annelation on the Changes of the Excitation Energy of the p Band

Abstract

For the group of 86 catacondensed and pericondensed benzenoid hydrocarbons, the theoretical estimates of the excitation energy of the p band, calculated by the Hiickel method and by the semiempirical method of the limited configuration interaction, as well as the experimental values of the same quantity, are plotted against the number of atoms of the respective molecules. In the plots thus obtained, the influence of the topology and size of the molecules on the changes of the theoretical and experimental values of the p-band excitation energy may be traced. A surprising similarity of plots for the three quantities mentioned has been found, and the importance of the molecular topology as the molecule characteristics is shown. Approximate rules based on the distribution of the "nodal points" in the highest occupied molecular orbital of the parent hydrocarbon have been derived, predicting the direction of the p-band shift with benzene ring annelation.(3) (a) A. Streitweiser, Jr.

Nonalternant hydrocarbons: a classification of excited states in acenaphthylene and pleiadiene (cyclohepta[de]naphthalene) families

“…One of the earliest studied isomerizations of CeHio is the [3,3] sigmatropic shift or Cope rearrangement2 of 1,5-hexadiene. The now classic experimental work of Doering and Roth suggested that the most facile route for this rearrangement involved a four-centered (chair-like) transition state.…”

Influence of annelation by benzene ring on electronic absorption spectra and on character of the singlet π‐π* transitions at polynuclear p‐quinones

“…The annelation diagram ( singlet absorption bands of p-quinones on the benzene ring annelation (or on the system size). The analysis of this graph leads to the relations resembling the shifts of p-bands in the annelation set of acenes and in the amelation type of phenes [26], where the first members of the annelation sets of the phene molecules are the molecules with C2" symmetry, while, in general, the members of these annelation sets have lower symmetry. Analogously it is possible to indicate the molecules of Q[m, n] for m = 0, n = 0, 1, 2, .…”

Shot Noise of Charge and Spin Current of a Quantum Dot Coupled to Semiconductor Electrodes

“…Using some perturbations of the Newns-Anderson metal model like gold, one can model semiconductors as titanium-dioxide and silicon [33][34][35][36][37][38] as seen in Fig.1. One such model which alternates both the site energies ε k1 , ε k2 and inter site couplings t 1 , t 2 with nearest neighbour in tight-binding picture has been introduced by Koutecky and Davison (KD) 33 , Fig. 1-(a).…”