Magnetic and electronic properties of rhodium clusters

We have used all-electron local (LDA) and nonlocal (GGA) approximations to the density-functional theory to determine binding energies, equilibrium geometries, vibrational frequencies, and magnetic properties of Rh, clusters (N less than or equal to 6). We present careful tests on the Rh-2 dimer that compare results as calculated with a large (18-single Gaussian) and a very large (23-single Gaussian) basis sets. While the smaller set of Gaussians leads to underconverged results, we find that the large basis set leads to converged results that are also in excellent agreement with the experimental data available for Rh,. The ground state of Ph-2 is confirmed to be a quintuplet, the trigonal Rh-2 is predicted to be a sextuplet, Ri(4) in its tetrahedral configuration is a singlet, Rh-5 sextuplet is a square pyramid, and Rh-6 septuplet is the octahedron. Results from several excited states are calculated and presented as well. It is found that LDA overestimates the binding energy but that GGA corrects this deficiency and predicts longer bond lengths.