Relativistic Effects and Gauge Invariance in Photon Absorption and Scattering

  • Nadejda BouldiEmail author
  • Christian Brouder
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 204)


The interaction of light with matter is often described within the semiclassical framework where light is represented by an external time-dependent vector potential. We show that the transition probabilities so obtained suffer from two drawbacks: their semi-relativistic limit is delicate and they are not gauge invariant. We describe how a gauge-invariant transition probability can be obtained, for which the semi-relativistic limit is well defined. In this way, we obtain a new spin-position term which is not negligible in x-ray magnetic circular dichroism at the K-edge of transition metals.


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© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC)UPMC Univ Paris 06, CNRS, UMR 7590, IRD, MNHNParis cedex 05France

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