First-order MP2 molecular properties in a relativistic framework

The first implementation of analytical first-order one-electron molecular properties at the Dirac-Coulomb MP2 level of theory is described. The formalism presented allows for the use of inactive spinors. The method has been applied to the calculation of parity-violation energies in H2X2 (X = O, S, Se, and Te). Electron correlation does not play an important role for this property in this kind of systems, but the effect is shown to be very geometry dependent.