Non-linear electric and magnetic properties obtained from cubic response functions in the random phase approximation Original Research Article

We derive cubic response functions in the Random Phase Approximation for calculations of non-linear frequency-dependent properties of molecules, and demonstrate an implementation of these functions using efficient computational algorithms. Illustrations are given by calculations of the frequency-dependent second hyperpolarizabilities, the frequency-dependent excited state polarizabilities and the three-photon transition amplitudes of the para-nitroaniline molecule, and by calculations of the frequency dependent magnetic second hyperpolarizabilities and their anisotropies for the first row hydrides isoelectronic with neon.