Impact-parameter dependence of2pσand1sσmolecular-orbital x rays produced by Nb-Mo collisions at 143 MeV

The impact-parameter dependence of molecular-orbital (MO) x rays has been measured as a function of x-ray energy for collisions of 143-MeV Nb ions with Mo. Different shapes for the impact-parameter dependence are found as a function of x-ray energy and are attributed to transitions to vacancies in the $2p\sigma$ and $1s\sigma$ orbitals, $C1\mathrm{}$ and $C2\mathrm{}$ continuum, respectively. $C1\mathrm{}$ MO x-ray emission probabilities were calculated from separately determined $2p\sigma$ vacancy-production probabilities and agree well in magnitude and shape with the measured values.