  Using the velocity map imaging technique, we studied and characterized the
process of Dissociative Electron Attachment (DEA) in polyatomic molecules like
Water, Hydrogen Sulphide, Ammonia, Methane, Formic Acid and Propyl Amine. We
present the details of these studies in a series of 5 articles. In the first
article here, we discuss the DEA process in gas phase water ($H_{2}O$ and
$D_{2}O$) molecules. Electrons of 6.5 eV, 8.5 eV and 12 eV are captured by
water molecules in neutral ground state to form $H_{2}O^{-*}$ ($D_{2}O^{-*}$)
resonant states which dissociate into an anion fragment and one or more
neutrals. Kinetic energy and angular distributions of the fragment anions
$H^{-}$($D^{-}$) and $O^{-}$ produced from the three negative ion resonant
states in the entire $2\pi$ scattering range are obtained. Unique angular
distribution patterns are observed at the 8.5 eV and 11.8 eV resonances showing
dissociation dynamics beyond the axial recoil approximation.
