Evidence for the lower limit of the reaction window of endoergicities applicable to triple-electron-capture reactions of fast-moving doubly charged ions with atoms and molecules

Abstract It has been proposed that the endoergicities of triple-electron-capture (TEC) reactions involving doubly charged ions must fall within a reaction window from 12 to 33 eV in order that the reactions have a finite probability. The upper limit has been confirmed previously in experiments involving Cl 2+ and O 2+ ions interacting with krypton. The lower limit was studied by reacting O 2+ with CS 2 molecules. It was shown that TEC reactions did not occur significantly below an endoergicity of about 10 eV, thus confirming the approximate lower limit for the window.