Frequency-dependent first hyperpolarizabilities using coupled cluster quadratic response theory

The first implementation of frequency-dependent hyperpolarizabilities is presented using coupled cluster quadratic response theory. The quadratic response functions are derived for the coupled clusted model hierarchy CCS, CC2 and CCSD and implemented for general frequency-dependent first hyperpolarizabilities. Calculations are performed on the second harmonic generation and the optical rectification hyperpolarizabilities of FH and the results are compared with experimental results and former theoretical investigations.