Electron-Impact Double Ionization to Investigate Electron Correlation
A full understanding of the complex correlated motion of electrons in atoms remains one of the fundamental challenges in atomic physics. The motion of atomic electrons can be described in terms of density functions in either configuration or momentum space. Single electron spatial density or momentum density gives the probability of finding an electron in a given region of space or with a given momentum. For pairs of electrons the corresponding densities can be expressed in terms of center-of-mass (Ql2) and relative (q12) coordinates. The calculations of Smirnov, Levin, Neudatchin, and Pavlitchenkov suggest that the q12 density will vary dramatically with the extent of correlation in the motion of the two electrons. 1, 2 This has been confirmed in more recent calculations by Wang and Smith for the first row hydrides, 3 and by Banyard and Sanders for H2, 4 Banyard and Mobbs for LiH, 5 and Mobbs and Banyard for Be. 6 These calculations demonstrate that the relative pair momentum density is a sensitive measure of electron correlation, but, until the present, direct experimental measurements of the densities have proved elusive. In this communication we describe measurements of center-of-mass pair electron momentum densities for the 3s electrons in magnesium using an electron-impact double-ionization technique and report progress on an experiment to measure relative two-electron momentum densities.
KeywordsMagnesium Helium Hydride Auger
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