Highly Excited States of Hydrogen Molecules. I.H2, HD, andD2

Highly excited states of hydrogen molecules have been formed by electron-capture collisions of 50—450-keV diatomic ions in hydrogen gas. Populations of the excited states ($n\ge 10$) have been determined by passing the molecules through an intense electric field which strips the excited electron from the molecule. The fraction of molecules in states $n\ge 10$ was approximately ${10}^{-3\mathrm{}}$ with ${\mathrm{D}}_2^{*}$ being approximately a factor of 2 greater than ${\mathrm{H}}_2^{*}$. The fractional yield of ${\mathrm{H}}_2^{*}$ varied as the stripping electric field to the $\frac{3}{4}$ power. Results are presented for molecular autoionization, excited-state population dependence on ion-source-electron energy, and state-mixing measurements.