The use of rigid organic microemulsions to fix liquid solutions for Mössbauer studies

Abstract

Rigid organic microemulsions containing submicroscopic droplets of liquid solutions of tin(IV) chloride in methanol and in ethylene glycol were prepared. In those systems where the walls of the cavities in the microemulsion carried negative charges and the hydrophilic groups of the surfactants and cosurfactants had H-bonding ability, it was shown that the internal surface of the cavities in the microemulsion was covered by a solvent layer separating Mössbauer-active SnCl 4 from this surface. On the other hand, solvated SnCl 4 was bound through the H-bonded solvent cluster to this surface-bound solvent by H bonds, resulting in recoilless γ-ray resonance absorption (Mössbauer effect). Thus, the rigid organic dispersion medium of these microemulsions behaved as a carrier enhancing the Debye-Waller factor for the quasi-liquid phase of the system, resulting in Mössbauer spectra characteristic of SnCl 4 in the bulk solution.