Double electron capture in O6++He collisions

As one kind of ubiquitous collision system, ${\mathrm{O}}^{6+}+\mathrm{He}$ deserves attentive study due to its theoretical significance in fundamental physics and applied value in fields like astrophysics or plasma physics. Specifically, in the case of the electron capture process, while a considerable number of measurements and calculations have focused on single electron capture, research is still inadequate on the double electron capture which contributes nearly 10% to the overall electron capture. In this work, a two-active-electron semiclassical asymptotic-state close-coupling method is used to calculate the total and $l-\mathrm{resolved}$ state-selective double electron capture cross sections of ${\mathrm{O}}^{6+}+\mathrm{He}$ collisions in the energy range 0.5–100 keV/u, accompanied by experimental measurements in the energy range 2.63–37.5 keV/u with an uncertainty of 16%, in good consistency. These theoretical and experimental data can fill gaps in the database of double electron capture in ${\mathrm{O}}^{6+}+\mathrm{He}$ collisions and provide insights for improving theoretical models in further research.