On The Collision Mechanism Of Bimolecular Reactions The Stripping Mechanism Of The Reactions Ar H2d2 Right Arrow Arh Hard D At Energies 20 Ev PDF Download

A simple apparatus is described which allows one to measure the velocity spectrum of the XH(+) or XD(+) ions, respectively, resulting from ion-molecule reactions of the type X(+) + H2(D2) forming XH(+) + H(XD(+) + D). The secondary ions are not accelerated after their formation. The incident X(+)-ions have kinetic energies between 20 and 200 cV. Furthermore, the velocity spectra are calculated which have to be expected for different collision models. (1) Complex model: All the atoms in the reactants participate in the collision. Every kind of collision between those limiting cases is conceivable, in which the relative kinetic energy of the reactants and the heat of reaction appear as internal energy of the product ion or as kinetic energy of both products (completely inelastic and elastic collision with atomic rearrangement, respectively). (2) Stripping model: The incident X(+)-particle hits only one atom of the hydrogen molecule in a completely inelastic collision without transfer of momentum to the second hydrogen atom. It is also shown that the cross section of the reaction becomes zero above a certain energy of the incident ion. This critical energy depends on the collision mechanism. It can be measured with the apparatus described. In addition an isotope effect of the order of 2 with respect to the critical energy is expected from the transfer of an H or D atom, respectively.