Experimental determination of the chemical changes in the electron densityon indium nuclei by the gamma-spectrometric Delta I-gamma/I-gamma method

The gamma -spectrometry method for determination of the relative change Del ta lambda (EC)/lambda (EC) in the partial probability lambda (EC) for the I n-114m decay branch by the electron capture (EC), when the nucleus is in di fferent chemical environments, was developed. The method is based on an exp erimental determination of the relative change DeltaI(gamma)/I-gamma in the intensity of the gamma -radiation which is emitted by the excited daughter Cd-114 nuclei after EC. The In-114m decay by EC in indium metal, In2O3 and InAs was compared. The largest DeltaI(gamma)/I-gamma=(2.5 +/-0.8).10(-4) h as been found for InAs relatively to In2O3. The chemical changes in the ele ctron density on the indium nucleus corresponding to the measured DeltaI(ga mma)/I-gamma values have been determined.