STEREOCHEMICAL INFORMATION ON $CH_{3}^{+}$ AND $NH_{3}^{+}$ DERIVED USING THE COULOMB EXPLOSION TECHNIQUE

$^{(1)}$ Z. Vager et al., Phys. Rev. Lett. 57 (1986), p. 2793. $^{(2)}$ E. P. Kanter et al., J. Chem. Phys. 85 (12), 1986, p. 7487.Author Institution: Physics Department, Weizmann Institute, Rehovot; Physics Department, Weizmann Institute, Argonne National LaboratoryStructure parameters for $CH_{3}^{+}$ and $NH_{3}^{+}$ molecular ions are extracted from Coulomb-explosion measurements utilizing 4.5-MeV ion beams. A typical experiment determines the relative velocities acquired by the atomic fragments as the molecular ion dissociates. The relative positions of the constituent nuclei, at the moment the dissociation starts, determine the total kinetic energy of the system and the way it is distributed among the atomic fragments. We are in the process of accumulating this type of information for several small molecular ions (total mass smaller than 50 a.m.u.) and have already succeeded to produce information not available through classical $methods^{(1,2)}$. The $CH_{3}^{+}$ and $NH_{3}^{+}$ ions data reveal structure parameters of these ions as well as correlations between the different internal degrees of freedom