Mössbauer studies of after effects of Auger ionization following internal conversion in organo-129mtellurium compounds

Abstract

The after effects of Auger ionization in diphenyl[129mTe]-telluride, dibenzyl[129mTe] telluride, and their dispersions in a solvent at 4.2 K, were compared with the same systems labeled with tellurium in the ground state, viz. 129Te. The Mössbauer emission, in the former case is preceded by Auger event and β decay, while in the latter case, it is preceded only by β decay. Three species were observed in the two compounds, I−, C6H5I or C6H5CH2I, and the third one has tentatively been identified as (C6H5)2I+ or (C6H5CH2)2I+. The formation of I− represents rupture of both bonds, i.e., complete fragmentation of the molecule. The probability of fragmentation was estimated with the help of matrix isolation experiments, as the electronically excited tellurium-129 ion formed by fragmentation of the molecule, following the Auger ionization, may interact with a neighboring organo-tellurium molecule in neat compounds, and enter combination. In about 85% of the events in case of diphenyl telluride and 55% in case of dibenzyl telluride, molecules escape complete fragmentation despite the fact that about 100 eV excitation energy may be deposited during charge neutralization. A novel mode for rapid disposal of energy is discussed.