The author thanks Peter Saalfrank for providing computational resources, for his comments on the manuscript, and for his support. The author thanks Foudhil Bouakline for valuable discussions. The author thanks the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) for financial support -project number 454020933. (Gefördert durch die Deutsche Forschungsgemeinschaft (DFG) -Projektnummer 454020933.)