Symmetry adapted auxiliary density perturbation theory

It is shown that the linear response equations of auxiliary density perturbation theory take a block diagonal form when symmetry adapted auxiliary functions are employed. Symmetry adapted linear combinations of primary and auxiliary functions were prepared by diagonalizing a nuclear attraction matrix and explicitly building real irreducible representations. Numerical results are provided as a proof of concept showing that all matrices required as building blocks of the response matrix take block diagonal form, together with the response matrix itself. Ionization energies and analytic Fukui functions are calculated to show the applicability on a small set of highly symmetric molecules.