Classical calculation of ionization and electron-capture total cross sections in ${\mathrm{H}}^{+}+{\mathrm{H}}_2\mathrm{O}$ collisions

We report total cross sections for single ionization and electron capture in ${\mathrm{H}}^{+}$ collisions with water molecules at impact energies $25\mathrm{keV}<E<5\mathrm{MeV}$. Calculations have been carried out by applying the independent-particle model and the eikonal–classical trajectory Monte Carlo (CTMC) method. We have also estimated fragmentation cross sections by multiplying the partial cross sections by the branching ratios measured in the photoionization experiments of Tan et al. [Chem. Phys. Lett. 29, 299 (1978)].

Figure 1

(Color online) Total cross section for single ionization in proton collisions with ${\mathrm{H}}_2\mathrm{O}$ as functions of the impact energy: Full line, present results for SI. Dash-dotted line, present results for TI. Previous calculations: dashed line, [12]; dashed–double-dotted line, [24]; asterisk ($\ast$), [11]. Experimental data for SI: ●, [4]; ∎, [5]; ◆, [9]; ▯ [7]; ▵ [8]. (The data of Ref. 8 correspond to $\mathrm{SI}+\mathrm{TI}$ for $15<E<100\mathrm{keV}$ and to SI for $E>500\mathrm{keV}$.)

Figure 2

(Color online) Total cross section for single electron capture in proton collisions with ${\mathrm{H}}_2\mathrm{O}$ as functions of the impact energy: Full line, present results for SEC. Dash-dotted line, present results for TI. Dashed line, present results for SEC using the modified IPM treatment of Ref. 28 [see Eq. (10)]. Experimental data for SEC: ●, [4]; ▶, [7]. Experimental data for $\mathrm{SEC}+\mathrm{TI}$: ◆, [3]; ▵, [8].

Figure 3

(Color online) Total cross sections for formation of ${\mathrm{H}}_2{\mathrm{O}}^{+}$, $\mathrm{O}{\mathrm{H}}^{+}$, ${\mathrm{H}}^{+}$, and ${\mathrm{O}}^{+}$ in the SI reaction, calculated using the branching ratios of Tan et al. [29] (a) and Olivera et al. [24] (b). Experimental data: ◆, [9], 엯, [8].