Measurement of the electron affinity of NO2

The translational energy dependence of the relative cross section for Cs+NO2→Cs++NO2− has been measured in the threshold region using crossed molecular beams. Good energy resolution in the center of mass is obtained with a time-of-flight technique for the Cs primary beam and by numerical analysis of the remaining c.m. energy spread. The data are well represented by convoluting a c.m. cross section with the experimental energy spreads. This relative cross section has a threshold at 1.39±0.05 eV and yields an adiabatic electron affinity for NO2: 2.50±0.05 eV.