Spectroscopic characterization of actinide materials

MRS Bulletin ◽  
2010 ◽  
Vol 35 (11) ◽  
pp. 889-895 ◽  
Author(s):  
R. Caciuffo ◽  
E. C. Buck ◽  
D. L. Clark ◽  
G. van der Laan
Keyword(s):  
Electronic Structure ◽  
Degrees Of Freedom ◽  
Inelastic Neutron Scattering ◽  
Occupation Number ◽  
Spectroscopic Characterization ◽  
Inelastic Neutron ◽  
Spectroscopic Techniques ◽  
Magnetic Fluctuations ◽  
Electronic Density ◽  
X Ray

Advanced spectroscopic techniques provide new and unique tools for unraveling the nature of the electronic structure of actinide materials. Inelastic neutron scattering experiments, which address temporal aspects of lattice and magnetic fluctuations, probe electromagnetic multipole interactions and the coupling between electronic and vibrational degrees of freedom. Nuclear magnetic resonance clearly demonstrates different magnetic ground states at low temperature. Photoemission spectroscopy provides information on the occupied part of the electronic density of states and has been used to investigate the momentum-resolved electronic structure and the topology of the Fermi surface in a variety of actinide compounds. Furthermore, x-ray absorption and electron energy-loss spectroscopy have been used to probe the relativistic nature, occupation number, and degree of localization of 5f electrons across the actinide series. More recently, element- and edge-specific resonant and non-resonant inelastic x-ray scattering experiments have provided the opportunity of measuring elementary electronic excitations with higher resolution than traditional absorption techniques. Here, we will discuss results from these spectroscopic techniques and what they tell us of the electronic and magnetic properties of selected actinide materials.

Spin Dynamics in the Metallic State of YBa2(Cu0.98 Zn0.02) 3O6+x

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3330-3334 ◽  
Author(s):  
Y. Sidis ◽  
P. Bourges ◽  
B. Hennion ◽  
R. Villeneuve ◽  
G. Collin ◽  
...  
Keyword(s):  
Inelastic Neutron Scattering ◽  
Spin Dynamics ◽  
Inelastic Neutron ◽  
Resonance Peak ◽  
Low Energy ◽  
Metallic State ◽  
Magnetic Fluctuations ◽  
Local Enhancement ◽  
Compound I ◽  
Nonmagnetic Impurities

Inelastic neutron scattering measurements have been carried out on a YBa2(Cu0.98-Zn0.02)3O 6+x single crystal in both underdoped (x = 0.7) and overdoped (x = 0.97) regimes. In the zinc substituted system, spin dynamics is drastically changed in respect to the pure compound: (i) the "resonance peak" almost vanishes, (ii) the spin gap is filled, (iii) new antiferromagnetic excitations are found at low energy. These new magnetic fluctuations, which persist in the normal state, account for a local enhancement of AF correlations around nonmagnetic impurities. Besides, it is worth emphasizing that features, not directly related to superconductivity, i.e., the contribution to the spin dynamics apart from the resonance peak and the "spin pseudo-gap" observed in the underdoped regime above T c , coexist with the new low energy magnetic fluctuations.

scholarly journals Synthesis, Crystal Structures, and Spectroscopic Characterization of Bis-aldehyde Monomers and Their Electrically Conductive Pristine Polyazomethines

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1498 ◽  
Author(s):  
Abdul Hafeez ◽  
Zareen Akhter ◽  
John F. Gallagher ◽  
Nawazish Ali Khan ◽  
Asghari Gul ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Spectroscopic Characterization ◽  
Spectroscopic Techniques ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Electrically Conductive ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Ft Ir

Bis-aldehyde monomers 4-(4′-formyl-phenoxy)benzaldehyde (3a), 3-methoxy-4-(4′-formyl-phenoxy)benzaldehyde (3b), and 3-ethoxy-4-(4′-formyl-phenoxy)benzaldehyde (3c) were synthesized by etherification of 4-fluorobenzaldehyde (1) with 4-hydroxybenzaldehyde (2a), 3-methoxy-4-hydroxybenzaldehyde (2b), and 3-ethoxy-4-hydroxybenzaldehyde (2c), respectively. Each monomer was polymerized with p-phenylenediamine and 4,4′-diaminodiphenyl ether to yield six poly(azomethine)s. Single crystal X-ray diffraction structures of 3b and 3c were determined. The structural characterization of the monomers and poly(azomethine)s was performed by FT-IR and NMR spectroscopic techniques and elemental analysis. Physicochemical properties of polymers were investigated by powder X-ray diffraction, thermogravimetric analysis (TGA), viscometry, UV–vis, spectroscopy and photoluminescence. These polymers were subjected to electrical conductivity measurements by the four-probe method, and their conductivities were found to be in the range 4.0 × 10−5 to 6.4 × 10−5 Scm−1, which was significantly higher than the values reported so far.

scholarly journals Etazene (N,N-diethyl-2-{[(4-ethoxyphenyl)methyl]-1H-benzimidazol-1-yl}-ethan-1-amine (dihydrochloride)): a novel benzimidazole opioid NPS identified in seized material: crystal structure and spectroscopic characterization

2020 ◽  
Author(s):  
Marta Siczek ◽  
Marcin Zawadzki ◽  
Miłosz Siczek ◽  
Agnieszka Chłopaś-Konowałek ◽  
Paweł Szpot
Keyword(s):  
Crystal Structure ◽  
Analytical Data ◽  
Chemical Characterization ◽  
Drug Market ◽  
Spectroscopic Characterization ◽  
Illegal Drug ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Full Characterization

Abstract Purpose The aim of the study was to present the spectroscopic characteristics and crystal structure of the etazene—a benzimidazole opioid, which appeared on the illegal drug market in Poland in the last weeks. Methods The title compound was analyzed by X-ray crystallography as well as gas and liquid chromatography combined with mass spectrometry. Spectroscopic techniques have also been used, such as nuclear magnetic resonance, infrared and ultraviolet-visible spectroscopies. Results We presented the identification and the broad chemical characterization of etazene, a synthetic opioid that has recently been introduced on the illegal drug market. Conclusions In this paper, we described single-crystal X-ray, chromatographic and spectroscopic characterization of a synthetic opioid that emerged on the new psychoactive substance (NPS) market in Poland. To the best of our knowledge, this is the first full characterization of etazene. Analytical data presented in the work can be helpful in identification and detection of the NPS in forensic and clinical laboratories.

scholarly journals Desolvation process in the flexible metal–organic framework [Cu(Me-4py-trz-ia)], adsorption of dihydrogen and related structure responses

CrystEngComm ◽  
2019 ◽  
Vol 21 (43) ◽  
pp. 6523-6535 ◽  
Author(s):  
Oliver Erhart ◽  
Peter A. Georgiev ◽  
Harald Krautscheid
Keyword(s):  
Structural Changes ◽  
Inelastic Neutron Scattering ◽  
Metal Organic Framework ◽  
Inelastic Neutron ◽  
Adsorption Behaviour ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Organic ◽  
Flexible Metal ◽  
Dft Modelling

Structural changes and the unusual H2 adsorption behaviour of a Cu2+-based MOF were studied by X-ray diffraction in combination with DFT modelling and by inelastic neutron scattering.

LATTICE DYNAMICS OF CALCIUM FLUORIDE: PART I. LYDDANE, SACHS, TELLER FORMULA, DIFFUSE X-RAY SCATTERING, AND SPECIFIC HEAT

1962 ◽  
Vol 40 (1) ◽  
pp. 74-90 ◽  
Author(s):  
S. Ganesan ◽  
R. Srinivasan
Keyword(s):  
Specific Heat ◽  
Calcium Fluoride ◽  
Inelastic Neutron Scattering ◽  
Interaction Force ◽  
Inelastic Neutron ◽  
Symmetry Operation ◽  
Absorption Frequency ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

The reported violation of the Lyddane, Sachs, Teller formula in calcium fluoride has been shown to arise from an error due to the non-application of a symmetry operation in the second neighbor fluorine–fluorine interaction in Cribier's work. By correct deduction of the force constants, the diffuse X-ray scattering measurements are shown to be in accord with the Lyddane, Sachs, Teller formula, but the specific heat calculation on this model is in disagreement with the experimental data.Reflection measurements in the infrared and dispersion of refractive index are shown to be consistent with the principal infrared absorption frequency near 40 μ and not near 51 μ as assumed in the previous model. The calculation of the specific heat using this new infrared frequency agreed with the measurements only at very low and very high temperatures.The two curves are brought into agreement by assuming that the non-Coulomb cross interaction force constant β1 between first neighbor calcium and fluorine decrease with the wave vector. The diffuse X-ray scattering was recalculated on the model, which explained the specific heat data, and was again found to be in agreement with the Lyddane, Sachs, Teller formula. It is suggested that detailed infrared and inelastic neutron scattering studies be made on this crystal.

scholarly journals Spectroscopy of light-molecule endofullerenes

2013 ◽  
Vol 371 (1998) ◽  
pp. 20120429 ◽  
Author(s):  
Malcolm H. Levitt
Keyword(s):  
Small Molecules ◽  
Degrees Of Freedom ◽  
Inelastic Neutron Scattering ◽  
Level Structure ◽  
Inelastic Neutron ◽  
Supramolecular Systems ◽  
Guest Molecules ◽  
Energy Level Structure ◽  
Rotational Degrees Of Freedom ◽  
Synthetic Routes

Molecular endofullerenes are supramolecular systems consisting of fullerene cages encapsulating small molecules. Although most early examples consist of encapsulated metal clusters, recently developed synthetic routes have provided endofullerenes with non-metallic guest molecules in high purity and macroscopic quantities. The encapsulated light molecule behaves as a confined quantum rotor, displaying rotational quantization as well as translational quantization, and a rich coupling between the translational and rotational degrees of freedom. Furthermore, many encapsulated molecules display spin isomerism. Spectroscopies such as inelastic neutron scattering, nuclear magnetic resonance and infrared spectroscopy may be used to obtain information on the quantized energy level structure and spin isomerism of the guest molecules. It is also possible to study the influence of the guest molecules on the cages, and to explore the communication between the guest molecules and the molecular environment outside the cage.

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