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The program EFFINO (Environment For FItting Nuclear Optics) evaluates Mössbauer absorption and time spectra both in nuclear forward scattering and in grazing incidence reflection geometry. Time‐integral prompt and delayed angular scan spectra are also treated. The time spectra are calculated by Fourier transformation from frequency to time domain. The electric quadrupole and magnetic dipole fields at the nuclear sites are considered static at present. The specimen in both forward scattering and grazing incidence is assumed to be a multilayer, with individual thickness and interface roughness (the latter only for the grazing incidence case at present) and electronic index of refraction. Up to eight different layers plus eight repetition periods of those layers are treated. Each layer may contain zero to eight nuclear sites (zero in all layers being prompt X‐ray reflectivity), with their own effective thickness or (for grazing incidence) their own complex nuclear index of refraction. From the forward scattering amplitude, a differential 4 × 4 propagation matrix is constructed for each layer. Several experimental spectra of the same or different type(s) can be fitted simultaneously. Correlations between parameters of the same or of different spectra can be introduced.

The μ+SR were measured on CsMgCl3 single crystals to elucidate the muonium formation and migration in isostructural magnetic halides. More than 60% of incident μ+ were found to form muonium and the fraction of the muonium shows little temperature dependence. A part of muonium located near Mg2+ ions with zero nuclear dipole moments gives a fast relaxing component in the spectra. It was concluded from the decrease of asymmetry and the peak of the relaxation rate of the recovered asymmetry that muonium migrates above 90 K.

Ar+-laser (λ=488 nm) irradiation of calcium gallate (CG) glass with the composition of 60CaO·39Ga2O3·Fe2O3 resulted in a distinct decrease in the IR transmittance (T) due to the formation of crystalline CaGa2O4 and CaGa4O9 phases. The Mössbauer spectrum of non-irradiated glass comprised a broad doublet due to distorted Fe3+(Td) withδ, Δ, andΓ of 0.20, 1.33, and 1.00 mm s−1, respectively. An additional doublet due to Fe3+(Td) was observed in the Ar+-irradiated glass andδ, Δ, andΓ were 0.17, 1.32, and 0.75 mm s−1, respectively. A decrease inT was also observed after the60Co γ-ray irradiation with doses ≥105Gy, and the precipitation of CaO, Ga2O3, and CaGa4O7 phases was confirmed by X-ray diffraction.

The measurement of the Mössbauer effect in a system excited with a periodic perturbation can provide information about it. For that purpose, the Mössbauer absorption of a source-absorber set which hyperfine parameters are well known, is measured at a constant relative velocity (i.e. at a defined spectral energy). The resulting Mössbauer absorption periodic signal provides information of the sample ac perturbation response. This approach has been used time ago to measure small tympanic vibrations (mechanical perturbations). In this work we present an extension of the vibration experiments, by measuring them at various absorber-source relative velocities within a constant-velocity strategy. As a demonstration test, the frequency response of a piezoelectric diaphragm in the 100 Hz–5 kHz range is obtained with a custom electronic counter. The experiments are performed using a 57Co(Rh) source and a 25- $\upmu$ m-thick stainless-steel absorber fixed to a piezoelectric diaphragm. Phase shifts and amplitude vibrations with velocities in the range from 1.5 $\upmu$ m/s to 20 mm/s are well characterized, extending the linearity limit well beyond the earlier suggested one of 1 mm/s.

The parity-violating mixing of the 17/2− and 17/2+ levels in93Tc nuclei, polarized by the tilted multifoil interaction, was measured by the observation of the forward-backwardγ-ray asymmetry. The nuclear polarization, induced by the tilted multifoils, was measured directly for the neighboring88,90Zr isomers. The forward to backward asymmetry was determined to be Aγ=(2.5±2.1) 10−3 which implies a parity violating matrix element ¦H PV )¦=(4.0±3.7)meV.

The Mössbauer effect of57Fe implanted into diamond structure semiconductors, Ge, Si and C, has been studied by in-beam implantation of57Fe ions, which were excited to the 14 keV state by a35Cl beam from a tandem Van de Graaff accelerator. The time between the stopping of the57Fe nucleus and the emission of the 14 keV γ-ray is determined by the lifetime (140 ns) of the 14 keV state. In each material the Mössbauer spectrum exhibits a doublet with velocity coordinates (in mm/s) at room temperature, relative to a sodium ferrocyanide absorber, as follows: diamond (−0.99, 1.10), silicon (−0.80, 0.21), and germanium (−0.88, −0.02). In silicon and germanium crystals the spectra were observed over the temperature range between 13 K and 870 K. The relative line intensities changed dramatically and the positions of the lines shifted systematically with temperature. In addition, channelling studies were made on iron that had been implanted into silicon.

Ferrites of the system CuCrxFe2−x O4, wherex=0,0.2,0.4, 0.6 and 0.8, have been studied by Mössbauer and IR absorption spectra. Mössbauer spectra were recorded at room temperature. The spectra of all samples showed two well defined Zeeman patterns corresponding to A and B sites. The effect of the variation of chromium substitution on the various hyperfine interactions has been discussed. The cationic distribution makes clear that all Cr3+ ions occupy octahedral sites. The IR spectra in the range 200–4000 cm−1 showed the presence of four bands. The high and low frequency bandsv 1 andv 2 belong to the tetrahedral and octahedral sites, respectively. Small bandsv 3 andv 4are observed around v2 and are assigned to the octahedral divalent metal-oxygen ion complexes and the lattice vibrations of the system, respectively.

The knowledge of muon transfer from protium to tritium is essentially theoretical and the different theoretical values disagree partially. Using solid hydrogen-tritium targets, with different tritium concentrations, we obtained precise experimental results for the transfer rate to tritium and the ppµ molecular formation rate. The time spectra of neutrons and alpha particles produced after dtµ fusion are used to determine the transfer rate λpt and the molecule formation rate λppµ.

This study refers to the effect of sodium polyacrylate concentration (1 to 5 mass %) and pH (10 to 12) on the synthesis of magnetic nanoparticles (magnetite–maghemite) and their characterization by Mössbauer spectroscopy. The magnetic particles were obtained by coprecipitation method using iron chloride (II) and iron chloride (III) as precursor reagents and sodium polyacrylate as stabilizing agent. All samples showed Mössbauer broad resonance lines in typical doublet and sextets patterns of magnetite or maghemite with corresponding wide particle size distributions. The stability of magnetic particles was carried out by measuring particle sizes with dynamic light scattering (DLS). The z-average values for magnetic particles were in the range 24 to 590 nm and no significant change in size was observed on aging by leaving this material in air for 20 days. X-ray diffraction patterns showed characteristic peaks of the spinel structure and have an increase in their broadening as the pH decreases, effect that is dominated by the decrease in crystallite sizes. The nanoparticles showed to be magnetic at pH 12 and at room temperature.