Excitation of the (a)over-tilde 3B1 and (A)over-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 (1b(1) -> 4a(1)) B-1,3(1) 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 degrees to 130 degrees. 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) over tilde B-3(1) and (A) over tilde B-1(1) states are also derived from the differential cross section results.