Christof Hättig

TL;DR: An analysis of the different contributions to excitation energies shows that the present scheme for the construction of the R12 pair functions leads in response theory to an unbalanced description of ground- and excited-state wave functions and needs to be generalized to carry the high accuracy of R12 methods over to response theory.

TL;DR: In this article, the first and second dipole hyperpolarizabilities were extended to describe more accurately the molecular response to strong and inhomogeneous external time-dependent electric fields.

TL;DR: In this article, the dielectric, refractivity, Kerr, and hyperpolarizability second virial coefficients for the helium and argon gases are evaluated for a wide range of temperatures using a semiclassical approach and the high quality frequency-dependent interaction induced electric polarizabilities.

TL;DR: A pair natural orbital (PNO)-based implementation of coupled cluster singles and doubles (CCSD) excitation energies that builds upon the previously proposed state-specific PNO approach to the excited state eigenvalue problem is presented.

TL;DR: Second harmonic generation hyperpolarizability B3LYP was found to perform best, i.e., to give the results closest to the CC3 ones, while for the geometric derivatives none of the considered functionals was able to give a consistent description for all the considered molecules.