To validate the implementation within the CP2K program package, splittings and oscillator strengths relying on the all-electron ZORA-Hamiltonian of Eq. ( ) were compared with the analogous implementation in ORCA featuring perturbative SOC relying on a Breit-Pauli-Hamiltonian . All calculations were performed using the Perdew-Burke-Ernzerhof with 25% Hartree-Fock exchange (PBE0) functional and TZP-ZORA basis sets . The first 10 excited states of the homologue series of H