Helium 6 Fully differential cross sections 4 Impact ionization 4 Ionization 4 Numerical methods 4 Projectile target interaction 4 Projectiles 4 Transition amplitudes 4 Wave functions 4 Above-threshold ionization 2 Angular distribution 2 Bound state 2 Close coupling 2 Close-coupling techniques 2 Computational complexity 2 Convergent close coupling methods 2 Convergent close couplings 2 Convergent close-coupling calculations 2 Coulomb-Volkov wavefunction 2 Couplings 2 Differential cross section 2 Dinger equation 2 Double ionization 2 Doubly excited levels 2 Eigenvalues and eigenfunctions 2 Electron emission 2 Electron emission energy 2 Electron impact-ionization 2 Electrons 2 Excitation amplitudes 2