The threshold photoelectron spectrum of mercury

The threshold photoelectron spectrum of mercury has been recorded over the energy range
(10–40 eV) which covers the region from the lowest state of the singly charged ion,5d106s(2S1/2), to the double charged ionic state, 5d9(2D3/2)6s(1D2). Synchrotron radiation has been used in conjunction with the penetrating-field threshold-electron technique to obtain the spectrum with high resolution. The spectrum shows many more features than observed in previous photoemission measurements with many of these assigned to satellite states converging to the double ionization limit.