Cascading interatomic Coulombic electron capture induced by a single incident electron in two- and three-center atomic systems

In the process of interatomic Coulombic electron capture, an incident free electron is captured at an atomic center <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi>A</a:mi></a:math> and the transition energy is transferred radiationlessly over a rather large distance to a neighboring atom <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mi>B</b:mi></b:math> of different species, upon which the latter is ionized. We consider two-step cascade processes where the electron emitted from atom <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mi>B</c:mi></c:math> is subsequently captured as well (either at center <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mi>A</d:mi></d:math> or yet another atomic center <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mi>C</e:mi></e:math>), leading to the emission of a second electron from one of the centers. We derive formulas for the cross section of this cascading interatomic Coulombic electron capture, which can reach the order of kilobarn for suitable parameters and exhibits a very strong dependence on the interatomic distances. The relevance of this process, which leads to a substantial rearrangement of the electronic configuration, is discussed in various two- and three-center atomic systems.