PNNL

Abstract

The Mg and Al K-alpha radiation used in standard laboratory sources for X-Ray Photoelectron Spectroscopy, XPS, is not naturally monochromatic because the spin orbit splitting of the Mg and Al 2p shells is not normally resolved. However, since the 2p spin-orbit splitting of the K-alpha1 and K-alpha2 X-Rays in these light atoms is small, it is normally ignored. In the present work, the consequences of the departure from monochromaticity is explicitly shown to be extremely small for the representative case of the C(1s) ionizations in the XPS of the pyrimidine molecule. This conclusion is general and does not depend on the particular molecule studied since the K-alpha1 and K-alpha2 BE splittings reflect the spin-orbit splittings in the X-Ray source.