Multiplet d States

Transition metals are numbered D3, D4, D5.Dn in the Solid State Table, n 

Let us now turn to the cl electrons in the monoxide scries. Following Hund s rule, for n — 2 values up through 5, all electrons have the same spin. Mn has one electron in each of the live cl orbitals, all with the same spin. Beginning with iron, the added electron is of opposite spin and the total spin decreases by one electron at each step. The total orbital momentum and the total angular momentum quantum number J of the ground stale follow rules of atomic physics that we need not consider in detail. For Mn , illustrated in Fig. 19-1, with one electron in each cl orbital, the total orbital momentum is zero (this state of zero orbital angular momentum is denoted by an S) and the spin is 5/2 in the ground state. (There arc six orientations of spin = —5/2, -3/2, — 1/2, 1/2, 3/2, and 5/2,. so the state is written S.) 

In order to identify this transfer energy with energies in the solid, we may imagine bringing the metallic ions together with the ions to form the solid, so 

The electronic structure of MnC) contains valence bands that are principally of oxygen 2/) character and a condtiction band that is principally of manganese 4.s character. The energy required to remove an electron from a Mn d state and to place it in the conduction band is. Sec the text for further description of the figure. [After Koilier and Falicov, 1974.J 

Electronic. structure of the transition-metal monoxides. The nictal-ion configuration has a formula (Ar)(3r/) Excitation energies (in eV) arc to a configuration (Ar)(3d) 4.s- If At (Kq. 19-2) is negative, metallic conductivity is expected. 

---