Journal ArticleIn a spectroscopic investigation of jet-cooled Rh2 by the resonant two-photon ionization method, an abrupt predissociation threshold is observed in a dense set of vibronic levels at 19 405?4 cm-1. Based on the high density of states expected in the rhodium dimer, the sharp definition of the predissociation threshold that is observed, and the validation of a similar conclusion in the case of V2, it is argued that predissociation occurs as soon as the energy of the separated ground state atoms is exceeded. On this basis the bond energy of Rh2 is assigned as D0(Rh2)=19 405 ?4 cm-1=2.4059?0.0005 eV. This value is compared to the results of other experiments and to theoretical calculations. The bond energy of disilver, D0(Ag2)=1.65?0.03 eV, provides a particularly useful standard of comparison, and suggests that 4d contributions to the bond energy of Rh2 amount to at least 0.76 eV
