Low Velocity Hydrogen Ion Scattering in Hydrogen, Water and Ammonia

Abstract

Improved technique has enabled more precise measurements to be made of the effective cross section for scattering of hydrogen, water, and ammonia for low velocity protons and of hydrogen for low velocity H₂⁺ and H₃⁺. From the measurements of proton scattering in hydrogen and ammonia and H₃⁺ scattering in hydrogen, and the use of certain assumptions, the average force laws can be evaluated and the energy of combination estimated in the first two cases. The proton affinities thus calculated for hydrogen and ammonia agree with previous estimates. For H₂⁺ in H₂ an evaluation of force law and an estimate of energy of combination cannot be made, but the large interaction is a phenomenon of some interest. Further increase in precision, separation of scattering from neutralization, and extension of measurements to lower velocities of ions is necessary also to evaluate the force law and proton affinity of water. As measurements of this kind can be made using many kinds of ions, each of which can be scattered in a great variety of gases, much information of value can be obtained such as force laws, proton affinity or absolute basicity of substances, energies of solvation of ions, etc.