Excitation of the a-tilde 3B1 and A-tilde 1B1 states of H2O by low-energy electron impact

We report measured and calculated differential cross-sections for inelastic scattering of low-energy electrons by water leading to excitation of the dissociative (1b1 → 4a1) 1,3B1 states. The measurements were taken using conventional energy-loss spectroscopy at incident energies of 9, 10, 12, 15, and 20 eV for scattering angles from 10° to 130°. The calculations were carried out using the Schwinger multichannel method, with a Born-dipole correction applied in the singlet excitation channel. Integral excitation cross sections for the a-tilde 3B1 and A-tilde 1B1 states are also derived from the differential cross section results.