Study of the electron donor‐acceptor properties of diamagnetic organic molecules via positronium reactions

William J. Madia, Alan L. Nichols, Hans J. Ache
1974 Journal of Chemical Physics  
or usefulness of any information, apparatus, product or proceu disclosed, or represents that its use would not infringe privately owned rights. Positrons, generated by the radioactive decay of certain nuclides, may, while losing their kinetic energy in collisions with surrounding molecules., combine with an electron to form an electron-positron bound state, the positronium atom (Ps). This species has a lifetime of about 10 to 10~ s which is too short for its reactions to be followed by
more » ... ollowed by conventional product analysis. The chemical reactions of positronium can be studied by observing changes in its average lifetime and decay modes wb Lch are dependent on the chemical reactivity and physical composition of its environment. This feature, as well as the simplicity of the species, makes the positronium atom a useful probe for the assessment of molecular properties via kinetic measurements. The annihilation of positronium in simple organic solvents has been comprehensively studied , and the effects following the addition of diamagnetic species have been observed. In the following, we should like to report the results of a preliminary study of the interactions of positronium with nitrobenzene and ortho, meta and para derivatives of nitrotoluene and dinitrobenzene in benzene solutions. Distinct differences in the rate constants for the reaction of positronium with the organic molecules were observed for the various systems, and an attempt was made to correlate these changes to certain molecular parameters and to the effects of steric interactions in these molecules. \ DISTRIBUTION OF THJS DOCUMENT IS UNLIMITED E 4604 nr,T I 2
doi:10.1063/1.1680797 fatcat:ebzgfwue6vdozmcixvb7ilrjaa