Resonant two-photon ionization spectroscopy of jet-cooled OsN: 520?418 nm

The optical transitions of supersonically cooled OsN have been investigated in the range from 19 200 to 23 900 cm?1 using resonant two-photon ionization spectroscopy. More than 20 vibronic bands were observed, 17 of which were rotationally resolved and analyzed. The ground state is confirmed to be 2?5/2, deriving from the 1?2 2?2 1?4 1?3 3?2 electronic configuration. The X 2?5/2 ground state rotational constant for 192Os14N was found to be B0 = 0.491921(34) cm?1, giving r0 = 1.62042(6) ? (1? error limits). The observed bands were grouped into three band systems with ?" = 7/2 and four with ?" = 3/2, corresponding to the three 2?7/2 and four 2?3/2 states expected from the 1?2 2?2 1?4 1?3 3?1 2?1 and 1?2 2?2 1?4 1?2 3?2 2?1 electronic configurations. In addition, two interacting upper states with ?"= 5/2 were observed, one of which is thought to correspond to a 1?2 2?2 1?3 1?3 3?2 2?1, 2?5/2 state. Spectroscopic constants are reported for all of the observed states, and comparisons to related molecules are made. The ionization energy of OsN is estimated as IE(OsN) = 8.80 ? 0.06 eV.