The structure of Nb3O and Nb3O+ determined by pulsed field ionization–zero electron kinetic energy photoelectron spectroscopy and density functional theory - Yang, Dong-Sheng; Zgierski, Marek Z; Rayner, David M; Hackett, Peter A; Martinez, Ana; Salahub, Dennis R; Roy, Pierre-Nicholas; Carrington Jr, Tucker (The Journal of chemical physics, 1995)