The objective of this thesis is to investigate the neutralization of He2+ in front of a metal surface. According to a commonly used sequential model, He2+ is firstly converted to He+ and then to He0. Two electrons are emitted incoherently by the two correspondingneutralization steps. As the ionization potentials of He2+ → He+ and He+ → He0 are 54.4 eV and 24.6 eV, respectively, the electron pair prefers one fast electron and one slow electron. In other words, a very unequal energy sharing between the two electrons is expected. The electron pair emission, upon the impact of 10 eV normal incident He2+ ions onto Ir(100) and Fe(100)-p(1×1)O surfaces, was studied by a two-electron coincidence spectrometer. In the two-electron coincidence spectra, we have found the electron pairs can be understood by the sequential model. However, we have also found the electron pair emission can only be explained by a non-sequential process. For these events, the two electrons can share the energy available to them continuously. To explain the non-sequential process, the correlation between the two emissions should be taken into account.