Precision Measurement of the Electron Affinity of Chlorine via High-Resolution Photoelectron Spectroscopy.

Chlorine (Cl 2 ) is a diatomic molecule used as an important industrial gas. However, the electron affinity (EA) of Cl 2 , a fundamental parameter for understanding chemical reactions, has no accurate experimental result available. The latest result of the EA value of Cl 2 is 2.50(20) eV reported in 1983. In the present work, we report the precision measurement of the EA of Cl 2 with the successive difference method via the high-resolution photoelectron spectroscopy of cryogenically cold chlorine anions Cl 2 - . The EA of Cl 2 is determined to be 19432(9) cm -1 or 2.4093(11) eV.