上海科技大学知识管理系统

The experimental generalized oscillator strengths (GOSs) for the valence-shell excitations of heavy water in 6.50-12.17 eV are determined by fast electron scattering with an incident electron energy of 1500 eV and an energy resolution of 80 meV. The experimental data of the A1B1←X1A1 transition between H2O and D2O show significant discrepancies around the minimum, and further theoretical calculations with nuclear effects accounted are recommended. The comparisons of the present GOSs of A1B1←X1A1 and B1A1←X1A1 transitions in D2O with theoretical calculations within the first Born approximation and the second Born approximation indicate that the higher Born terms become prominent at large momentum transfers. In particular, the GOSs of the dipole-forbidden transition 1A2←X1A1 are extracted, benefiting from the present high-energy electron scattering, where most of electronic dipole-forbidden transitions are not involved. By extrapolating the GOSs to the zero momentum transfer, the optical oscillator strengths for the corresponding dipole-allowed transitions are determined, which provide an independent cross-check for previous optical measurements. Moreover, the integral Born cross sections are scaled to an accurate level with the aid of the binding energy-excitation energy-scaling method. The relevant experimental data in this work can supplement the molecular database with electron collision data involving heavy water. © 2022 American Physical Society.