The charge-transfer process ${\mathrm{O}}^{8+}+\mathrm{H}\mathrm{}\left(1s\right)\mathrm{}\to {\mathrm{O}}^{7+}+{\mathrm{H}}^{+}$ is considered for ${\mathrm{O}}^{8+}$ impact energies from 0.025 to 200 keV/amu, using the atomic base $S$ matrix formulation represented by time-dependent bases which denote moving atomic orbitals. In the evaluation of the $S$ matrix, models of two extreme types, the unitarized model and the absorption model, are introduced. The numerical results show that there is only a small difference between the cross sections obtained using the respective models for impact energies above 0.5 keV/amu, while the cross section due to the unitarized model becomes smaller than one-half of that obtained with the absorption model at an impact energy of 0.05 keV/amu. The data are also compared with other calculations of the same process. For the investigation of the validity of our formula, the unitarized formula is also applied to the processes ${\mathrm{H}}^{+}+\mathrm{H}\mathrm{}\left(1s\right)\mathrm{}\to \mathrm{H}+{\mathrm{H}}^{+}$ and ${\mathrm{He}}^{2+}+\mathrm{H}\mathrm{}\left(1s\right)\mathrm{}\to {\mathrm{He}}^{+}+{\mathrm{H}}^{+}$. The results are in good agreement with the experimental data.

• Received 13 February 1978

DOI:https://doi.org/10.1103/PhysRevA.18.2005