X-ray transitions in hydrogen-like,helium-like and lithium-like boron

The boron K X-ray spectra produced in heavy ion collisions using gas targets are reported. The observed X-ray transitions are used, to identify the one, two and three electron series of boron. The observed X-ray transition energies are found to agree well with theoretical calculations. A relatively large number of transitions involving double K-shell vacancies are observed. These transitions represent the first observation of double K-shell vacancies produced in collisions where the inner shell vacancies occur from electron promotion via molecular orbitals of the quasi-molecule formed during the collision.