Plasma Effects in Annulene Molecules

Abstract

Some plasma effects of the pi electrons in annulene molecules are studied. The dispersion relation for plasma oscillations, obtained by using Hückel molecular orbitals in the second quantization formalism, is found to describe soundlike waves. The resulting polarization response of the pi electrons causes a spatial modulation of the interaction potential between two pi electrons. The polarization response defines the natural correlation units in annulenes to be quartets in all but the angular momentum l = ± 2n states of 4n-annulenes and zero angular momentum states, where the correlation unit is a pair of electrons. Correlation is discussed by using the modified interaction potential with a Wannier hamiltonian in pair and quartet equations. The effect of band alternation is considered in connection with the variation of induced currents in unsaturated annulenes with temperature.