Search for cluster effects in x-ray production by fast hydrogen molecules

A search was made to observe a difference in the x-ray yield from equal velocity ${\mathrm{H}}^{+}$ and ${\mathrm{H}}_2^{+}$ projectiles of 300-1200 keV/amu incident on thin metallic-film targets. Two different experimental techniques are described in which we observed x-rays arising from ionization of electrons with binding energies from 73 to 778 eV. To within the experimental uncertainty of approximately 1% no difference in yield could be detected.