We present the vacuum ultraviolet (VUV) spectrum of H2O produced by electron impact at 200 eV. A total of 25 spectral features is identified at a resolution of 0.5 nm over the wavelength range of 40 to 280 nm. Absolute emission cross sections were measured for each of these features. These features are all attributed to excited states of the dissociation products (H, 0, 0+). The Lyman-&ggr; feature which is the brightest spectral feature for electron induced fluorescence of H2O from the UV to near-IR has a cross section of 6.3¿1.0¿10-18 cm2 at 200 eV and contributes 74% of the total measured emission cross section in the EUV. |