Twisted-electron-impact single ionization of an H2O molecule by multicenter distorted-wave calculations

Abstract

We report theoretical investigation of the twisted-electron-impact single-ionization dynamics of an ${\mathrm{H}}_{2}\mathrm{O}$ molecule. The triple-differential cross sections for $1{b}_{1}$, $3{a}_{1}$, $1{b}_{2}$, and $2{a}_{1}$ orbitals are obtained by a twisted-electron-impact multicenter distorted-wave method. The coplanar asymmetric kinematic condition is adopted at incident electron energy ${E}_{i}=250$ eV and ejected electron energy ${E}_{e}=10$ eV. By integrating the impact parameter, all possible rotation angles ${\ensuremath{\varphi}}_{k}$ of the projectile are averaged for the triple-differential cross section, which is independent of the orbital angular momentum and varies as a function of opening angle ${\ensuremath{\theta}}_{k}$. The results show that the ionization by a plane-wave projectile is more likely than by a twisted-electron projectile if the scattering angle is smaller than a critical value. However, when the scattering angle exceeds the critical point, the twisted-electron projectile can possess higher ionization probability, which will reach a maximum when the opening angle numerically approaches the scattering angle.