Relative single (black) and double (red) photoionization cross section of Mg near the 2p thresholds.
SRC Newsflash—Ralf Wehlitz and Pavle Juranic publish work on "Relative single- and double-photoionization cross sections of Mg around the 2p → nl resonances"
Investigating the interactions of electrons in an atomic system is at the heart of understanding quantum mechanics. We have studied the interaction of magnesium (Mg) atoms with soft x-rays (i.e. high-energy light) coming from a synchrotron light source (SRC). At just the right energy of the light an electron of the Mg atom can be moved to a higher, empty energy level inside that atom. With increasing energy, higher and higher steps in this "Rydberg ladder" can be reached. These steps get closer and closer in energy and eventually the electron is free and leaves the atom. By doing a quantitative analysis of those "ladders" in Mg with a much higher precision than was done before, we not only improved previous results but also found that one of the ladders ended at the wrong energy! Besides this correction, our new state-of-the-art data provide the basis for stringent tests of different theoretical models when they become available. On a practical note, our data can also be used for energy calibration at other experiments.