Static and dynamic first hyperpolarizabilities from time-dependent auxiliary density perturbation theory

A new approach for the calculation of static and dynamic hyperpolarizabilities in the framework of auxiliary density perturbation theory is derived. It takes advantage of the Wigner's 2n+1 rule. As a byproduct dynamic quadratic response equations are obtained. Even though the final equations are similar to other approaches they present subtle differences due to their rooting in auxiliary density functional theory. The numerical stability and accuracy of the new approach is validated with respect to other theoretical and experimental results. (c) 2012 Wiley Periodicals, Inc.