Asymptotic behavior of the electron-atom Compton profile due to the intramolecular H-atom motion in H 2 .

We report the asymptotic behavior of the electron-atom Compton profile due to the intramolecular H-atom motion in H 2 . The experiment has been performed at a scattering angle of 135° and at incident electron energies from 1.0 to 2.2 keV, thus covering a momentum transfer ( K ) range from 15.8 to 23.5 a.u. It is shown that with the increase in K , the Compton profile changes in shape and becomes more symmetric. Furthermore, it is found that the experiment reaches the limit of sufficiently large K at an incident electron energy of 2.0 keV, where the plane-wave impulse approximation is applicable to directly relate the Compton profile to the momentum distribution of the H atom.