ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The dipole moments (μ), polarizabilities (α), hyperpolarizabilities (β), and second-order hyperpolarizabilities (γ) of polyenes, polyynes, and polyphenyls have been calculated by a finitefield method with the PM-3 parameterization of the semiempirical MNDO Hamiltonian at the optimum geometries. These results were compared to experimental values obtained from EFISH and THG measurements. The calculations reproduce the magnitudes of β and γ, as well as the effect of the substituents and the effect of bond alternation on β and γ. The coefficients of the power law, which describes the dependence of β and γ on the number of π centers, were calculated. For β, exponents of 1.5-2.2 and 0.03-0.04 were obtained for polyenes and polyynes, respectively, and for γ, exponents of 3.9-4.9, 2.9-3.3, and 2.5-2.7 were obtained for polyenes, polyynes, and polyphenyls, respectively. These results confirm the efficiency of enhancing γ by insertion of C = C double bonds into a chain. © 1992 John Wiley & Sons, Inc.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560440409
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