Inelastic squared form factors of the vibronic states of B1Σu+, C1IIu, and EF1Eg+for molecular D2 studied by high-energy electron scattering

The inelastic squared form factors of the valence-shell excitations of D2 were measured by high-energy electron scattering and calculated by the multireference single-and double-excitation configuration interaction method in the present work. It is found that for the B1Eu+ state of D2, the theoretical calculation cannot satisfactorily reproduce the inelastic squared form factors with a higher vibrational quantum number. For the vibronic states of C1 pi u and EF1 sigma g+ of D2, obvious discrepancies between our electron-scattering results and theoretical calculations are found. Similar phenomena observed for H2, HD, and D2 may be attributed to electronic-vibrational coupling and the failure of the first Born approximation at an incident electron energy of 1500 eV. Furthermore, the present inelastic squared form factors of D2 are in good agreement with the ones of H2 and HD, which indicates that there is no isotope effect for the electronic matrix elements of H2, HD, and D2 in the momentum space.

Automated summary

The inelastic squared form factors of valence-shell excitations in D2 were studied using high-energy electron scattering and theoretical calculations. Discrepancies were found between the experimental results and theoretical calculations for the B1Eu+ state and vibronic states of C1 pi u and EF1 sigma g+. This can be attributed to electronic-vibrational coupling and the failure of the first Born approximation at an incident electron energy of 1500 eV. The inelastic squared form factors of D2 were in good agreement with H2 and HD, indicating no isotope effect for electronic matrix elements in the momentum space.