Ultraviolet photoelectron spectra of atoms

In the case of atoms UPS is unlikely to produce information which is not available from other sources. In addition many materials have such low vapour pressures that their UPS spectra may be recorded only at high temperatures. The noble gases, mercury and, to some extent, the alkali metals are exceptions but we will consider here only the specttum of argon. 

From the discussion in Section 7.1.2.3 we can deduce that the state arising from the ground configuration of Ar is However, the ground configuration of Ar gives rise to two states, Pi/2 since L= and S = j, giving a term, and J = or. These two states of 

The He I ultraviolet photoelectron spectra of Kr and Xe appear similar to that of Ar but the ionization energy decreases and the spin-orbit coupling increases with increasing atomic number, as illustrated by the data in Table 8.1. 

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