Multicenter continuum distorted wave with eikonal initial state model for single ionization in ion-molecule collisions: Differential electron emission from water under energetic ion impact

A multicenter continuum distorted wave with eikonal initial state model for single ionization of molecules by energetic ion impact is developed. The multicenter nature of the molecular ion is explicitly taken into account, within the framework of the independent electron approach, where the interaction between the ejected electron and the residual molecular ion is described by an anisotropic model potential. The method is employed to calculate doubly and singly differential cross sections of the water molecule by energetic ${\mathrm{H}}^{+}$, ${\mathrm{C}}^{6+}$, and ${\mathrm{O}}^{8+}$ projectiles. The discussion of the results is primarily focused on the emission of low-energy electrons, where the evaluated cross sections are compared with experimental and available theoretical data.

Figure 1

DDCS for single ionization as a function of the electron emission angle for different electron energies for the 1 MeV ${\mathrm{H}}^{+}$ projectile impact. Present CDW-EIS results are shown as heavy solid line, solid line, and dashed line, obtained with static-exchange, static, and spherical static potentials, respectively. The experimental data are shown as symbols [45].

Figure 2

DDCS for single ionization as a function of the electron emission angle for different electron energies for the 250 keV ${\mathrm{H}}^{+}$ projectile impact. Present CDW-EIS results are shown as heavy solid line, solid line, and dashed line, obtained with static-exchange, static, and spherical static potentials respectively. Symbols are the experimental data, while red and blue lines are the theoretical prior CDW-EIS and CTMC results, respectively, all taken from [31].

Figure 3

DDCS for single ionization as a function of the electron emission angle for different electron energies for the 4.5 MeV/amu ${\mathrm{O}}^{8+}$ projectile impact. Present CDW-EIS results are shown as heavy solid line, solid line, and dashed line, obtained with static-exchange, static, and spherical static potentials respectively. Symbols are experimental data from [48]. Solid red and blue lines are the prior and the post CDW-EIS results, respectively [9]. The solid green line shows the 3CW result [20].

Figure 4

DDCS for single ionization as a function of the emission emission angle for different electron energies. Present CDW-EIS results are shown as heavy solid line, solid line, and dashed line, obtained with static-exchange, static, and spherical static potentials, respectively. Symbols are experimental data from [21] for ${\mathrm{C}}^{6+}$ and [51] for ${\mathrm{O}}^{8+}$ impacts. Solid red and blue lines are the prior and the post CDW-EIS results for ${\mathrm{C}}^{6+}$ [9] and for ${\mathrm{O}}^{8+}$ [51] ions, respectively. The green line (${\mathrm{C}}^{6+}$, $\epsilon$ = 19.2 eV) shows the 3CW data [20]; the dotted line (${\mathrm{O}}^{8+}$, $\epsilon$ = 5 eV) is the CTMC data from [46].

Figure 5

DDCS for single ionization as a function of electron ejection energy for different emission angles for the 4.5 MeV/amu ${\mathrm{O}}^{8+}$ projectile impact. Present CDW-EIS results are shown as heavy solid line and solid line, obtained with static-exchange and static potentials, respectively. Symbols and the solid red lines show the experimental and the prior CDW-EIS results, respectively, from [48].

Figure 6

SDCS for ionization as a function electron emission angle. The present CDW-EIS results are shown as heavy solid line and solid line, obtained with static-exchange and static potentials, respectively. Symbols are experimental data [48, 51] and the prior and post CDW-EIS results are given by solid red and blue lines [48], respectively. The dotted line is the CTMC results from [46].

Figure 7

Energy distribution of SDCS for the 6 MeV/amu-${\mathrm{C}}^{6+}+{\mathrm{H}}_2\mathrm{O}$ collisions. Theory: present CDW-EIS obtained with static-exchange potential (heavy solid line), static potential (solid line), FBA from [21] (dot-dashed line), and CTMC from [28] (dashed line). Experimental results are from [21] (full circle) and [52] (open circle).