One of the major focuses in the study of nonlinear optics in recent years has been the microscopic description of the second and third order π-electron virtual excitation processes in organic and polymeric systems. In particular, the question of correlation in systems of reduced dimensionality has been under intense study. Important evidence for the inadequacy of independent particle theories such as Huckel theory in these systems has been provided by the experimental discovery that below the one-photon 11Bu π-electronic state exists a two-photon 21Ag state in linear chain polyenes, in direct contradiction with these simple theories. It was then demonstrated that a proper account of the electron correlation resulting from electron-electron interactions was required in order to obtain the correct ordering of these two states.

Date Published: 21 December 1988
PDF: 9 pages
Proc. SPIE 0971, Nonlinear Optical Properties of Organic Materials, (21 December 1988); doi: 10.1117/12.948209

Published in SPIE Proceedings Vol. 0971:
Nonlinear Optical Properties of Organic Materials
Garo Khanarian, Editor(s)