Molecular Nonlinear Optical Susceptibilities in Condensed Phases
Abstract
A microscopic theory for the nonlinear optical response and susceptibilities of molecular materials with localized and delocalized electronic states (e.g. molecular assemblies, conjugated polymers, aggregates and monolayers) was developed. The theory, which properly accounts for many-body effects, is based on the derivation of coupled reduced equations of motion for the material variables, which determine the optical response. The present formulation maps the calculation of optical nonlinearities onto solving the dynamics of coupled nonlinear oscillators and overcomes the difficulties associated with the local-field approximation. An operational definition of the nonlinear coherence-size N(c), which controls the cooperative enhancement of the optical response is developed. A real-space representation of the optical response of conjugated polyenes is developed by using the Wannier representation to derive equations of motion for coupled two-site oscillators representing correlated electron-hole pairs. The resulting elementary excitations are shown to be intermediate between the molecular (Frankel) and the semiconductor(Wannier) excitons, and clearly resemble charge transfer excitons.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 16, 1993
- Accession Number
- ADA270200
Entities
People
- Shaul Mukamel
Organizations
- University of Rochester