Cross sections for the electron impact excitation of the B₁, A₁and A₁dissociative electronic states of water

Absolute differential and integral cross section measurements for electron impact excitation of the dissociative B 1 , A 1 and A 1 electronic states of water are described. These are very important channels for the production of OH ( X 2 Π, ν) radicals, as well as for understanding the origin of the atmospheric Meinel bands. The energy range of our measurements is 20–50 eV, with the angular range of the differential cross section data being 10°–90°. Where possible comparison of the present cross sections with the corresponding results from theoretical calculations is made, the level of agreement between them being found to be quite marginal.