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Published July 9, 1993 | public
Journal Article

Relation Between Bond-Length Alternation and Second Electronic Hyperpolarizability of Conjugated Organic Molecules

Abstract

The solvent dependence of the second hyperpolarizability, γ, of a variety of unsaturated organic compounds has been measured by third harmonic generation at 1907 nanometers. It is seen that the measured y is a function of solvent polarity. These solvent-dependent hyperpolarizabilities are associated with changes in molecular geometry from a highly bond-length alternated, polyene-like structure for a formyl-substituted compound in nonpolar solvents, to a cyanine-like structure, with little bond-length alternation, for a dicyanovinyl-substituted compound in polar solvents. By tuning bond-length alternation, γ can be optimized in either a positive or negative sense for polymethine dyes of a given conjugation length.

Additional Information

© 1993 American Association for the Advancement of Science. 29 January 1993; accepted 19 May 1993. The research was performed, in part, at the Center for Space Microelectronics Technology, Jet Propulsion Laboratory (JPL), California Institute of Technology, and was supported, in part, by the Strategic Defense Initiative Organization-Innovative Science and Technology Office, through an agreement with the National Aeronautics and Space Administration (NASA). Support at the Beckman Institute by the Air Force Office of Scientific Research (grant F49620-92-J-01 77) is also acknowledged. C.B.G. thanks the JPL director's office for a postdoctoral fellowship. G.B. thanks the National Research Council and NASA for a resident research associateship at JPL.

Additional details

Created:
August 20, 2023
Modified:
October 19, 2023