Fivefold differential cross sections for electron-induced double ionization of outer and inner valence (1t2 and 2a1) molecular orbitals of CH4

•The double ionization of the methane molecule is investigated within the 1st Born approximation.•The fivefold differential cross sections appear as strongly dependent of the target orientation.•The double ionization mechanisms, namely, Shack Off and Two Step 1, are clearly identified.

We report in this work theoretical differential cross sections for the double ionization of oriented methane molecular subshells, namely, the 1t2 and 2a1 levels, impacted by 1 keV electrons. The present calculations are provided within the first Born approximation with a target molecule described by means of a single-center wave function. A strong dependence of the fivefold differential cross sections versus the target orientation is observed in particular when the double ionization process is studied orbital by orbital. In all the kinematical conditions considered, we point out the signature of the well-known mechanisms involved in double ionization collisions.

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