AM1 parameters for cobalt and nickel.

We report the parameterization of AM1 for the elements Co and Ni. The basis sets for both metals contain one set each of s-, p- and d-orbitals. AM1 parameters are now available for H, C, N, O and F (which use the original AM1 parameters), Al, Si, P, S, Cl, Ti, V, Cr, Co, Ni, Cu, Zn, Br, Zr, Mo and I. The performance and typical errors of AM1 are discussed for Co and Ni and compared with available NDDO Hamiltonians.