Theory of electron-capture cross section, alignment, and orientation in low-energy collisions

A Landau Zener model with rotational and degenerate Stark effect coupling is - developed to calculate the partial and total cross sections of ionic states produced by collision of highly charged ions with neutral atoms. I apply this model to C⁶⁺H(1s) collisions and obtain the total cross section and L-distributions. The results are compared with other calculations and available experimental data. I extend this single Landau-Zener crossing model to multiple Landau-Zener crossings and apply it to O⁵⁺ + H(1s) and C³⁺ + H(1s) collision processes. The total and partial cross sections are in agreement with available experimental data. I employ this model to calculate the mean value of atomic states produced by the A^Zp+ + H(1s) collision process. I apply it to C⁶⁺ H(1s) and B³⁺ + He collision processes and obtain the alignment and orientation parameters. When comparing the orientation parameter of B³⁺ + He → B²⁺(2p) + He⁺ collisions with the experimental data, the result is very good.

Using the Demkov's contour integral expression for transition amplitudes, I de- rive a new model for the above collision process and apply it to C⁶⁺H(1s) collisions. I obtain the total cross section. When comparing with the experimental data and other calculations, the result is excellent in the low velocity region.