Coupled Hartree-Fock calculations of molecular hyperpolarizabilities

The second-order SCF perturbation method for the calculation of electrical polarizabilities is extended to the third order for the calculation of hyperpolarizabilities. Exploratory calculations for the hyperpolarizability of FH suggest that the convergence of the third-order theory is comparable to that of the second, and confirm the sensitivity of β to choice of basis set as found by other workers.