Understanding the electron capture mechanisms during heavy-ion collisions

Besides the direct Coulomb and multiple ionization, ionization caused by the electron capture is found to be a vital mechanism for the x-ray emissions in heavy-ion collisions. This mechanism associated with M-shell ionization is more complex than that for the K- and L-shell ionization and not understood yet. We have developed a theoretical method to understand the M x-ray production cross sections. Here we have considered both the M -K and M -L capture processes of the target atoms by the changed charge state of the projectile ions to witness a good agreement between the present theory and past experiments. We have first verified the present theory with a few representative cases of the carbon, oxygen, and fluorine projectile ions colliding with the lead and bismuth targets at energies ranging from 0.8 to 6.0 MeV/u. Next, we have validated the worth of its predictions through neon ion-induced M x-ray production of lead and bismuth targets. We believe the current knowledge of the M x-ray production mechanisms will play a significant role in understanding the different aspects of the heavy-ion collision physics.