A systematic preparation of new contracted Gaussian‐ type orbital sets. VII. MINI ‐3, MINI ‐4, MIDI ‐3, and MIDI ‐4 sets for transition metal atoms

Two minimal contracted Gaussian‐type orbital (CGTO) sets are developed for the transition metal atoms. The expansion terms for the first set, MINI‐3, are 4, 3, 3, and 3 for s‐type CGTOs and others are all three. The abbreviation would be (4333/33/3) where the slash divides symmetry. The expansion terms for the other set, MINI‐4, is (4333/43/4). The split‐type basis sets, MIDI‐3 and MIDI‐4, are derived directly from MINI‐3 and MINI‐4, MINI‐3 and MIDI‐3 provide the outer‐shell orbital energies which are far better than those by single‐zeta (SZ) STOs. MINI‐4 and MIDI‐4 provide the outer‐shell orbital energies which are almost as good as those by double‐zeta (DZ) STOs. The total energies given by the present sets are better than those of SZ except for MINI‐3 for Sc and Ti: the energies by MINI‐4 and MIDI‐4 are only 0.8–1.7 a.u. higher than DZ. The basis sets were tested on the Cu2 molecule, where a large basis set was also used.