DETERMINATION OF THE ELECTRON-AFFINITIES OF MOLECULES USING NEGATIVE-ION MASS-SPECTROMETRY

The electron affinities of sulfur hexafluoride, nitrobenzene, two chlo roethylenes, and hexafluorobenzene have been obtained by analyzing the temperature dependence of thermal electron attachment negative ion ma ss spectra. The electron affinities are as follows: SF6, 1.07 +/- 0.07 eV; C6H5NO2, 1.0 +/- 0.06 eV; C6F6, 0.83 +/- 0.2 eV; C2Cl4, 0.64 +/- 0.03 eV; C2HCl3, 0.40 +/- 0.22 eV. The values support the literature v alues for SF6 and C6H5NO2 and the chloroethylenes. On the basis of the se results, an experimental procedure for measuring molecular electron affinities is presented.