Electric quadrupole interaction in hafnium sulphates

A coincidence system is developed which gives a time resolution of =0,8 ns for the 133–482 keV -ray cascade of¹⁸¹Hf. It is applied to the study of EQI in hafnium sulphate salts. In the case of Hf(SO₄)₂ the interaction strength of _Q = 157.8 ± 0.5 MHz is obtained, together with the assymetry parameter =0.531±0.005 and the field distribution parameter =0.003±0.001. The data are compared with point-charge model calculations.A similar set of EQI data is also derived for another unstable and unidentified hafnium sulphate structure.     

Electric quadrupole interaction and its temperature variation at100Rh in Be metal

The nuclear quadrupole interaction at the¹⁰⁰Rh probe nucleus in a Be host is measured from 4.2–968 K using time-differential perturbed γ-γ angular correlations of the 84–75 keV cascade in the de-excitation of¹⁰⁰Rh. The sources were prepared by recoilimplanting the parent¹⁰⁰Pd activity produced in a heavy-ion reaction. The temperature variation of the electric field gradient can nicely be fitted by aT ^3/2 law. We discuss the electric field gradient and its temperature dependence in the light of various systematics. The data are also compared with the predictions of the conduction electron charge shift model suggested by Bodenstedt and Perscheid.     

Electric quadrupole interaction of the 75 keV state of100Rh in a beryllium matrix

The quadrupole interaction frequencyv _q =eQV _zz /h = 8.92(9) MHz was observed for the 75 keV state of¹⁰⁰Rh in a polycrystalline beryllium matrix by use of the e^?-γ time differential perturbed angular correlation technique. The measured spin rotation pattern is hardly disturbed in spite of the fact that the source was produced by an isotope separator implantation of¹⁰⁰Pd into a beryllium foil without any after-treatment.     

The quadrupole interaction of100Rh in various intermetallic compounds of palladium

The nuclear quadrupole interaction of the 75 keV excited state of¹⁰⁰Rh in the ordered intermetallic compounds PdHg, PdPb₂ PdSb and PdTe was measured. Using an estimate for the nuclear quadrupole moment of the 75 keV state in¹⁰⁰Rh and point ion lattice sums for the lattice electric field gradient (EFG) at the Rh site, the electronic contributionV _zz ^el to the total EFG was derived.V _zz ^el was found to be correlated with the average valence electron concentration in the compounds studied. In the case of PdPb₂, the temperature dependence of the quadrupole interaction was also studied and found not to follow theT ^3/2 rule which is observed in virtually all pure noncubic metals.Work partially supported by U.S. Department of Energy.     

Niobium hydride studied by the electric quadrupole interaction of100Rh

NbH_x (x=0.83, 0.72) was studied between 90K and 450K by observing the quadrupole interaction of¹⁰⁰Rh with the TDPAC method. The transition from a static interaction at low temperatures to the motional narrowing limit in the non-cubic beta phase and the cubic alpha’ phase is well observed.     

Electric quadrupole orientation of iridium isotopes in rhenium

The quadrupole frequenciese ² qQ/h, for^{186, 188–190}Ir in a Re single crystal have been determined by nuclear orientation at temperatures down to 2 mK. Using a modeldependent value of +1.0 b for the quadrupole moment of the ground state of¹⁸⁹Ir, the electric field gradient of IrRe at 0 K is found to be–3.6×10¹⁷ V·cm^–2. The value is consistent with systematics proposed by Raghavan et al. Using this EFG, quadrupole moments are deduced for^{186, 188, 190}Ir.     

Temperature dependence of the quadrupole interaction of100Rh in a Cd lattice

The quadrupole interaction frequency |v _q| = |eQV _zz /h|0 = 8.71 ± 0.11 MHz was measured for the 75 keV state of¹⁰⁰Rh in a polycrystalline cadmium matrix by use of the γ-e^? and γ-γ time differential perturbed angular correlation (TDPAC) techniques. The temperature dependence of the electric quadrupole coupling constant for¹⁰⁰Rh in Cd is similar to those of other impurities in Cd metal.     

The temperature dependence of the quadrupole interaction of100Rh in a Zn lattice

The¹⁰⁰Pd radioactivity was implanted into a pure Zn host with the help of an isotope separator. The temperature dependence of the quadrupole interaction was studied by time-differential measurements of the 84 keVγ- 75 keVK-conversion angular correlation. We conclude that electrons contribute significantly to the electric field gradient at the Rh site, but that local effects due to the 4d electrons of Rh are probably small.     

Electric quadrupole interaction of recoil-implanted zinc in cadmium

The electric quadrupole interaction of the 605 keV 9/2⁺ state of ⁶⁷Zn in Cd metal was measured by the recoil implantation technique combined with the DPAD method (DIMPAD). The result, ν_Q = eQV_ZZ/h = 39.0(4) MHz (T = 373 K), is compared with the known quadrupole coupling constants in the Zn-Cd system.     

Electric quadrupole interaction of Ce isomers in tin

The quadrupole coupling constants for 10⁺ Ce isomers have been measured in a polycrystalline Sn host. The quadrupole moment ratios are Q[¹³⁸Ce(10⁺)]: Q[¹³⁶Ce(10⁺)]: Q[¹³⁴Ce(10⁺)]=11.45(14)1.71(16). The temperature dependence of the EFG was measured in the range 160–468 K.Incumbent of the Arye Dissentshik Career Development Chair.We thank Dr. A. Abbas for submitting to us the seniority scheme wave functions prior to publication.     

Temperature dependence of the electric quadrupole interaction at scandium impurities in zirconium and hafnium

The PAC probe⁴⁴Sc was employed to study the magnitude and temperature dependence of the electric quadrupole interaction at the site of the transition metal Sc in the hexagonal host lattices Zr and Hf. In Zr ∼ 100% of the probe atoms were situated on regular lattice sites and a quadrupole interaction frequency of υ_Q=7.8(1)MHz was measured at room temperature. For Hf the fraction of the probe atoms on regular lattice sites was smaller and a damping of the interaction pattern (υ_Q=9.3(5)MHz at 293 K) could not be excluded. The temperature dependence of the electric field gradient in both host lattices was found to be weak.     

Temperature dependence study of the quadrupole interaction of111Cd in antimony

A power law dependence has been observed for the temperature dependence of the quadrupole interaction of the 247 keV state of¹¹¹Cd in antimony, which is similar to that observed for¹²¹Sb and¹²³Sb in antimony.Supported in part by the US Energy Research and Development Administration.     

Temperature dependence of the nuclear quadrupole interaction and the Knight shift in rhenium metal

The temperature dependences of the static nuclear quadrupole interaction and the Knight shift in rhenium metal were investigated for 2K ≦ T ≦150 K by the method of Nuclear Acoustic Resonance (NAR). For the quadrupole interaction ¦e²qQ/h¦ an increase occurs from 255.2(5) MHz at 2 K to 257.2(8) MHz at 150 K in¹⁸⁷Re [269.5(7) to 271.5(10) in¹⁸⁵Re] whereas for the Knight shift a slight decrease from 1.14(4)% at 2K to 1.10(8)% at 150 K [1.16(6) to 1.12(10)] is found.     

Electric quadrupole interaction of181Ta in Pd and Zn

A strong electric field gradient (EFG) has been observed at¹⁸¹ Ta in Pd and Zn metals using DPAC technique. The value of the EFG in Pd is found to be 12.5(8)×10¹⁷ V/cm² with an asymmetry parameter () of 0.33(2). The value of the EFG in Zn has the same value as in the Pd metal, but the asymmetry parameter has the value 0.36(3). The variation of EFG in Pd with temperature has shown a weak dependence. The results are interpreted in terms of oxygen trapping at Hf atoms during the sample preparation.     

Electric quadrupole interaction of 212Rn isomers in Bi

The electric quadrupole interaction of the ²¹² Rn 8⁺ and 6⁺ isomers in a Bi single crystal was measured. The experimental results together with a shell-model calculation of the quadrupole moments provide a calibration of the electric field gradient for Rn impurities in Bi, to be used in future quadrupole-moment measurements of Rn isomers. A two-level analysis procedure was employed for the combined data of the 8⁺ and 6⁺ isomers.     

Electric field gradient at100Rh in HCP zirconium and gadolinium

The measurement of QI frequencies at¹⁰⁰Rh in Zr and Gd reveal that the electronic contribution to the EFG is quite large. The value of ¦K¦ is 8 for¹⁰⁰RhZr whereas it is 45 for¹⁰⁰RhGd. The temperature variation of¹⁰⁰RhZr neither follows T^1.5 nor has a linear T dependence.     

Electric quadrupole interaction at181Ta in RNi5 compounds

The time differential perturbed angular correlation measurements in PrNi₅, NdNi₅, GdNi₅, DyNi₅ and ErNi₅ rare-earth intermetallics with¹⁸¹Ta as probe nuclei have revealed that these impurity nuclei experience a non-axial electric quadrupole interaction. In all the cases, except in GdNi₅, the interaction frequency has a single value in the range 15–20 MHz with asymmetry parameter 0.98. In GdNi₅, however, there are two interaction frequencies (13.61 MHz and 26.89 MHz), the former being the dominant one (90%) with 0.35 and the latter (10%) with 0.98. It is concluded that in all cases the probe nuclei experiencing the highly asymmetric electric field gradient (efg) occupy the unique Ni(3g) site. Annealing studies have shown that in the case of GdNi₅ the interaction gets highly damped, while there is negligible effect in the other cases. The temperature variation of the efg in all cases seems to follow the empiricalT ^3/2 relation.