Photoelectron spectra and structure of the Mnn(-) anions (n = 2-16)

Photoelectron spectra of the Mnn(-) anion clusters (n = 2-16) are obtained by anion photoelectron spectroscopy. The electronic and geometrical structures of the anions are computed using density functional theory with generalized gradient approximation and a basis set of triple-ζ quality. The electronic and geometrical structures of the neutral Mnn clusters have also been computed to estimate the adiabatic electron affinities. The average absolute difference between the computed and experimental vertical detachment energies of an extra electron is about 0.2 eV. Beginning with n = 6, all lowest total energy states of the Mnn(-) anions are ferrimagnetic with the spin multiplicities which do not exceed 8. The computed ionization energies of the neutral Mnn clusters are in good agreement with previously obtained experimental data. According to the results of our computations, the binding energies of Mn atoms are nearly independent on the cluster charge for n > 6 and possess prominent peaks at Mn13 and Mn13(-) in the neutral and anionic series, respectively. The density of states obtained from the results of our computations for the Mnn(-) anion clusters show the metallic character of the anion electronic structures.