Grj. Williams, NEAR-RESONANT CONTRIBUTION TO THE HYPERPOLARIZABILITY IN BENZOPORPHRINS, Journal of molecular structure. Theochem, 102, 1993, pp. 185-189
A theoretical investigation of the frequency-dependence of the second
hyperpolarizability in the 400-750 nm spectral region is carried out f
or model benzoporphrins using the sum over states method in conjunctio
n with the random phase approximation and Pariser-Parr-Pople electron
theory. The calculations examine the near-resonant contribution of one
- and two-photon processes to the magnitude of the hyperpolarizability
in the visible region of the spectrum. Results indicate that these on
e- and two-photon processes are primarily determined by the nature of
the low energy electron states of the benzoporphrin systems.