Accurate Moessbauer line-shape measurements including interference in [sup 182]W, [sup 183]W, [sup 191]Ir, and [sup 159]Tb

We have made precise final state interference measurements using very intense Moessbauer sources and an exact line-shape analysis. Two transitions in tungsten metal, as well as one in iridium metal and one in terbium oxide, have been studied. The interference parameters 100[beta] found are [minus]1.3(3) for the 99.1-keV transition in [sup 183]W, [minus]1.2(1) for the 100.1-keV transition in [sup 182]W, [minus]0.71(8) for the 129.4-keV transition in [sup 191]Ir, and [minus]0.48(5) for the 58.0-keV transition in [sup 159]Tb. All values agreed with theory to within error. Our measurement of 1.16(2) cm/s for the [sup 191]Ir linewidth agrees with other Moessbauer measurements and shows no indication of hyperfine broadening, but disagrees with some non-Moessbauer measurements reported in the literature. The tungsten and terbium transitions also show no signs of broadening or splitting.