Photoelectron spectroscopy of PbS −

Abstract

The photoelectron spectrum of the gas phase diatomic anion, PbS − has been recorded with 2.540 eV photons. Transitions from the X 2 Π PbS − anion ground state to the X 1 Σ neutral PbS ground state are observed and assigned. The adiabatic electron affinity of PbS was determined to be 8461 cm −1 (1.049 eV). From this value and an energetic cycle, the dissociation energy of PbS − dissociating into the ground states of Pb and S − was found to be 55.4 kcal/mole (2.40 eV). From a Franck–Condon analysis of the spectrum, the anion’s bond length, vibrational frequency, and anharmonicity constant were determined to be r e=2.390 A ̊ , ω e=367 cm −1 , ω eχ e=2.2 cm −1 , respectively.