Fully differential cross-section measurements for electron-impact ionization of neon and xenon

We present a combined experimental and theoretical investigation of the fully differential cross section for electron-impact ionization of neon and xenon. The experiments were performed under coplanar asymmetric kinematics, at intermediate incident electron energies, and for a range of scattered electron detection angles. The experimental results are compared with three calculations: a convergent close-coupling calculation, a distorted-wave Born approximation (DWBA) calculation with inclusion of the Gamow factor, and a hybrid $\mathrm{DWBA}+R$-matrix calculation. The comparison between the experimental and theoretical results highlights the importance of the description of postcollision interaction, and the results exhibit interesting orbital-dependent differences.

Figure 1

(Color online) Measured and calculated triple differential cross sections for electron-impact ionization of the $1s$ orbital of helium, under kinematic conditions of $E_0=150\mathrm{eV}$ and $E_b=10\mathrm{eV}$. Experimental results with the MAC turned on (open circles) and off (full circles) are shown.

Figure 2

(Color online) Measured and calculated triple differential cross sections for electron-impact ionization of the $2s$ orbital of neon, under kinematic conditions of $E_0=150\mathrm{eV}$ and $E_b=10\mathrm{eV}$. Experimental results with the MAC turned on (open circles) and off (full circles) are shown, with the experimental data normalized to the CCC calculation at ${\theta }_a=-15°$.

Figure 3

(Color online) Measured and calculated triple differential cross sections for electron-impact ionization of the $2p$ orbital of neon, under kinematic conditions of $E_0=150\mathrm{eV}$ and $E_b=10\mathrm{eV}$. Experimental results with the MAC turned on (open circles and crosses, corresponding to different deflections) and off (full circles) are shown, with the experimental data normalized to the DW2-RM calculation at ${\theta }_a=-15°$.

Figure 4

(Color online) Measured and calculated triple differential cross sections for electron-impact ionization of the $2p$ orbital of neon, under kinematic conditions of $E_0=150\mathrm{eV}$ and $E_b=10\mathrm{eV}$. Experimental results with the MAC turned on (open circles and crosses, corresponding to different deflections) and off (full circles) are shown. Both theoretical data sets have been normalized to the second lobe of the binary maxima.

Figure 5

(Color online) Measured and calculated triple differential cross sections for electron-impact ionization of the $5p$ orbital of xenon, under kinematic conditions of $E_0=150\mathrm{eV}$ and $E_b=10\mathrm{eV}$. Experimental results with the MAC turned on (open circles) and off (full circles) are shown, with the experimental data normalized to the DW2-RM calculation at ${\theta }_a=-15°$.

Figure 6

(Color online) Measured and calculated triple differential cross sections for electron-impact ionization of several orbitals of neon and xenon, under kinematic conditions of ${\theta }_a=-15°$, $E_0=150\mathrm{eV}$, and $E_b=10\mathrm{eV}$. Experimental results with the MAC turned on (open circles) and off (full circles) are shown.