Analysis of linear and quadratic optical response of mixed Langmuir-Blodgett films of stearic acid and 5-CT

Authors

Marc in het Panhuis, University of WollongongFollow
R W. Munn, UMIST

RIS ID

19041

Publication Details

in het Panhuis, M. & Munn, R. W. (2000). Analysis of linear and quadratic optical response of mixed Langmuir-Blodgett films of stearic acid and 5-CT. Journal of Chemical Physics, 113 (23), 10691-10696.

Abstract

Published experimental optical second-harmonic generation (SHG) results for mixed films formed between stearic acid and the mesogen 5-CT (4^″-n-pentyl-4-cyano-p-terphenyl) are reanalyzed. Experimental refractive index results for the pure films are used to deduce molecular polarizabilities in order to calculate local fields. At low and high fractions of 5-CT, a consistent interpretation of the SHG is obtained using a mean molecular response based on a fixed axial hyperpolarizabilityβ_LLL for the mesogen, but at high mesogen fractions molecular tilt makes small off-diagonal componentsβ_LLM≈−β_LLL/40 essential. At intermediate fractions the treatment can interpret the SHG only by requiring molecular tilt not found in the experiments, implying that a more detailed structural model is required.