Hyperpolarizabilities of Push-Pull Polyenes: Molecular Orbital and Valence-Bond Charge-Transfer Models
J.W. Perry, S.R. Marder, F. Meyers, D. Lu, G. Chen, William A. Goddard III, J.L. Brédas, B.M. Pierce
Abstract
In this paper we review two theoretical approaches that illustrate the relationships between molecular (hyper)polarizabilities and bondlength alternation (BLA). In one approach, we employ sum-overstates calculations at the INDO-SDCI level on (CH_3)_2N-(CH=CH)_4-CHO, including an external, static, homogeneous electric field that unes the degree of ground-state polarization and BLA. In the second approach, we use a simple semiclassical model, wherein the mixing of valence bond (VB) and charge-transfer (CT) states along a BLA coordinate is treated. Qualitatively, the two approaches give very similar structure-property trends, that are consistent with experimental hyperpolarizability data on donor-acceptor polyenes. The agreement of the calculated trends reflects the importance of VB-CT energetics in determining them.
Group Members
Perry, J., Marder, S., Meyers, F., Lu, D., Chen, G., III, W. A. G., Brédas, J., & Pierce, B. (1995). Hyperpolarizabilities of Push-Pull Polyenes: Molecular Orbital and Valence-Bond Charge-Transfer Models. *In: Polymers for Second-Order Nonlinear Optics ; ACS Symposium Series, No. 601; American Chemical Society, 1995, pp.45–56.*. https://doi.org/10.1021/bk-1995-0601.ch003