K. Mohanalingam et al., FIRST HYPERPOLARIZABILITIES OF SOME PUSH-PULL OLEFINS MEASURED BY THEHYPER-RAYLEIGH SCATTERING TECHNIQUE, Synthetic metals, 82(1), 1996, pp. 47-51
First hyperpolarizabilities of a series of donor-acceptor substituted
ethylenes and butadienes have been measured using the hyper-Rayleigh s
cattering technique. Keeping the donor group fixed as dimethylamino, t
he second-order nonlinear coefficient beta in these aliphatic systems
has been measured and is shown to increase as a function of the accept
or strength with the exception of the cyano group. beta values of the
substituted butadienes are correlated with their bond length alternati
on parameter [delta r] obtained from semi-empirical calculations. It i
s shown that even in these small push-pull olefins, it is possible to
generate a variety of ground state structures by choosing a suitable a
cceptor with a fixed donor.