Impact-parameter treatment of high-velocity electron capture from diatomic molecules at fixed orientation

Scattering of charged particles at high velocity from diatomic molecules is formulated in the impact-parameter treatment using a Fourier transform of the amplitude in the quantum-mechanical treatment. Probabilities and total cross sections are evaluated for electron capture for a fixed orientation of the intermolecular axis. Total cross sections, integrated over projectile impact parameters, for capture from ${\mathrm{H}}_2$ predict variations of a factor of 2 or more for various orientations of the molecular axis. Capture from heteronuclear diatomic molecules is also considered.