Search results for "Samarium"

Infrared evolved gas analysis during thermal investigation of lanthanum, europium and samarium carbonates

2003

Abstract The characterisation of rare earth elements carbonates (REECs) was performed by thermal analysis (TG–DTG) combined with simultaneous infrared evolved gas analysis–Fourier transform infrared (EGA–FTIR) spectroscopy. The TG–DTG curves were obtained using the Perkin-Elmer PC series TGA-7 thermogravimetric analyser in the temperature range 25–800 °C both in dynamic air and nitrogen atmosphere. La 2 (CO 3 ) 3 · n H 2 O, Eu 2 (CO 3 ) 3 · n H 2 O and Sm 2 (CO 3 ) 3 · n H 2 O were analysed, the dehydration and decarbonation steps were investigated and the water content was calculated. The trace rare earth elements in lanthanum, europium and samarium carbonates were determined by Philips PU…

Evolution of quadrupole collectivity in N=80 isotones toward the Z=64 subshell gap: The B(E2;2+1→0+1) value of 142Sm

2015

It was shown that the evolution of the B(E2; 2+ 1 → 0+ 1 ) values in N = 80 isotones from Te to Nd is affected by the underlying subshell structure. This manifests itself in the observation of the local suppression of the B(E2) value at Z = 58 with respect to the neighboring nuclei 136Ba and 140Nd. To investigate this shell sensitivity toward the Z = 64 subshell gap, the B(E2; 2+ 1 → 0+ 1 ) value of the unstable nucleus 142Sm was measured utilizing the projectile Coulomb excitation technique. The radioactive ion beam (RIB) experiment was performed at the REX-ISOLDE facility at CERN. The B(E2) value of 32 (4) W.u. reflects the impact of the π(1g7/2 2d5/2) subshell closure at Z = 64 with resp…

Mono(cyclooctatetraenyl)samarium Complexes: the Return of the Normally “Inaccessible” Bis(trimethylsilyl)amido Derivative

1999

Ceria-based electrolytes prepared by solution combustion synthesis: The role of fuel on the materials properties

2016

Ce0.8Sm0.2O2 − xpowders were synthesized by solution combustion synthesis using citric acid, cellulose and sucrose as single, or intimately mixed, fuels. The powders were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, N2sorption at −196 °C, H2-temperature programmed reduction and thermogravimetric analyses. Textural properties of the powders were shaped by the peculiar employed fuel. The study of reducibility revealed that oxygen vacancies formation is mainly influenced by both parameters, specific surface area and total pore volume. The different tendency toward reduction played a key role in sintering under reducing atmosphe…

New synthetic strategies for the enhancement of the ionic conductivity in Ce0.8Sm0.2O2-x

2013

Introduction Samarium-doped ceria has been widely investigat-ed for electrochemistry applications as full density elec-trolyte for intermediate temperature solid oxide fuel cells (IT-SOFC), between 500°C and 800°C [1]. One of the main challenges for the ceria-based electrolytes is to decrease the resistivity at the grain boundary zone, especially in this low temperature range. Microstructure and morphology of the powder play a fundamental role on the densification behaviour and grain boundary properties, thus affecting the overall conductivity of electrolytes [2]. In this light, solution combustion syn-thesis (SCS) represents a flexible method to produce ultra fine powders with suitable mic…

Structure of low-lying states in 140Sm studied by Coulomb excitation

2016

The electromagnetic structure of 140Sm was studied in a low-energy Coulomb excitation experiment with a radioactive ion beam from the REX-ISOLDE facility at CERN. The 2+ and 4+ states of the ground-state band and a second 2+ state were populated by multistep excitation. The analysis of the differential Coulomb excitation cross sections yielded reduced transition probabilities between all observed states and the spectroscopic quadrupole moment for the 2+ 1 state. The experimental results are compared to large-scale shell model calculations and beyond-mean-field calculations based on the Gogny D1S interaction with a five-dimensional collective Hamiltonian formalism. Simpler geometric and alge…

EPM calculations of E2/M1 mixing ratios for even samarium isotopes 146–152Sm

1987

Abstract The M1 operator and the E2/M1 mixing ratios, Δ (E2/M1), are discussed in the framework of the extended phonon projection model (EPM). The model is applied to 146, 148, 150, 152 Sm to describe their M1 properties. Comparison is made between the EPM, the consistent- Q formalism (CQF) of the basic interacting-boson approximation (IBA-1) and the experimental Δ(E2/M1) data. Both theoretical approaches give reasonably good results and parameter systematics.

The gas-phase chemiionization reaction between samarium and oxygen atoms: A theoretical study

2004

The Sm + O chemiionization reaction has been investigated theoretically using a method that allows for correlation and relativistic effects. Potential energy curves have been calculated for several electronic states of SmO and SmO+. Comparison with available spectroscopic and thermodynamic values for these species is reported and a mechanism for the chemiionization reaction Sm + O is proposed. The importance of spin–orbit coupling in the excited states of SmO, in allowing this chemiionization reaction to take place, has been revealed by these calculations. This paper shows the metal-plus-oxidant chemiionization reaction.

Half-lives, neutron emission probabilities and fission yields of neutron-rich rubidium isotopes in the mass regionA=96 toA=100

1979

Neutron-rich rubidium isotopes were produced by thermal-neutron induced fission of235U and were isolated by surface ionization and mass separation. The new isotope (51 ±17) ms100Rb was identified. The half-lives of the rubidium isotopes with mass numberA=96 toA=100 were measured using neutron multiscaling or gamma multispectrum analysis. Measurements of the delayed-neutron emission probabilityP n of99Rb and of the fission yields of97Rb,98Rb, and99Rb were performed.

Production of neutron rich isotopes in fission. A study for RNB facilities

2002

Abstract The theoretical model for calculations of the fission product yields in the light-particle induced fission is discussed. A comparison of the production cross sections in fission of 238 U by protons, thermal and fast neutrons, and photons is presented. The results of studies of the very asymmetric fission of 238 U by protons and neutron at the moderate energy are reported.