Photoelectron spectroscopy of PbO-

The 351 nm photoelectron spectrum of PbO- has been recorded with 9 meV resolution. Transitions from the *II,,2 PbO-ground state anion to the X ‘Z+ neutral ground state and three excited states (a I, b O-, and A O+) are observed. The adiabatic electron affinity of PbO is determined to be 0.722(6) eV. From a Franck-Condon simulation of the spectrum we obtain r,(PbO-) = 1.995 ( 15) A, and observation of vibrational hot bands enables measurement of w.(PbO-)=588 ( 15) cm-‘. Elec-tronic energies of the excited states are reported, and our results ldentlfy a new excited state while suggesting a corrected term energy for the bO- state. 1