Analytic calculation of first-order molecular properties at the explicitly correlated second-order Moller-Plesset level: basis-set limits for the molecular quadrupole moments of BH and HF.

The analytic calculation of first-order properties has been implemented in the DALTON program at the level of explicitly correlated second-order Moller-Plesset perturbation theory (MP2-R12). The implementation has been accomplished for MP2-R12 theory based on standard approximations A, A', and B, using an auxiliary basis for the resolution-of-the-identity approximation, with and without a frozen core. MP2-R12 first-order molecular properties have been calculated analytically for a few small test molecules.

Double ionization of fluorinated benzenes: hole localization and delocalization effects.

The dense double ionization spectra of all the twelve fluoro-substituted benzene molecules are investigated in great detail by Green's function ADC2 calculations and a two-hole density mapping. Double ionization is shown to provide an extremely sensitive tool of electronic structure analysis. The calculations evidence and measure quantitatively how the charge distribution is dictated by the complex interplay between the resilience of the aromatic ring electronic structure and the disruptive effect of the electronegative halogen substituents.