Continuum distorted wave-eikonal initial state 10 Distortion (waves) 10 High energy physics 10 Impact ionization Ionization 10 Atoms 6 Multiple ionization 6 Charge density waves 4 First Born approximation 4 Inert gases 4 Inner-shell ionization 4 Ionization of gases 4 Proton 4 Proton impact 4 Protons 4 Single ionization 4 Theoretical study 4 Anti-particle collisions 2 Antiproton 2 Born 2 Branching ratio 2 CDW-EIS 2 Calculations 2 Classical trajectory monte carlo methods 2 Collisional contributions 2 Differential cross section 2 Double ionization 2 Electron 2 Electron emission 2 Electrons 2