Fig. 7. Experimental and TDDFT-calculated N K-edge XAS pre-edge regions for (a) (^AdFL)Ni(NMes) (3), and (b) (^AdFL)Ni(NAd) (4). Calculations were initiated from spin-unrestricted B3LYP single points using the CP(PPP) basis set on Ni and the ZORA-def2-TZVP(-f) basis set on all other atoms. Energies for the calculated spectra were adjusted using a linear correction presented as Fig. S15.† Unrestricted Kohn–Sham orbitals corresponding to the acceptor MOs involved the excitation giving the ca. 395 eV pre-edge peak are plotted at an isovalue of 0.03 au.