Search results for " epr"
showing 10 items of 85 documents
Optical, Structural and Paramagnetic Properties of Eu-Doped Ternary Sulfides ALnS2 (A = Na, K, Rb; Ln = La, Gd, Lu, Y)
2015
Eu-doped ternary sulfides of general formula ALnS2 (A = Na, K, Rb; Ln = La, Gd, Lu, Y) are presented as a novel interesting material family which may find usage as X-ray phosphors or solid state white light emitting diode (LED) lighting. Samples were synthesized in the form of transparent crystalline hexagonal platelets by chemical reaction under the flow of hydrogen sulfide. Their physical properties were investigated by means of X-ray diffraction, time-resolved photoluminescence spectroscopy, electron paramagnetic resonance, and X-ray excited fluorescence. Corresponding characteristics, including absorption, radioluminescence, photoluminescence excitation and emission spectra, and decay k…
Dynamics of correlations due to a phase noisy laser
2012
We analyze the dynamics of various kinds of correlations present between two initially entangled independent qubits, each one subject to a local phase noisy laser. We give explicit expressions of the relevant quantifiers of correlations for the general case of single-qubit unital evolution, which includes the case of a phase noisy laser. Although the light field is treated as classical, we find that this model can describe revivals of quantum correlations. Two different dynamical regimes of decay of correlations occur, a Markovian one (exponential decay) and a non-Markovian one (oscillatory decay with revivals) depending on the values of system parameters. In particular, in the non-Markovia…
Gd-based single-ion magnets with tunable magnetic anisotropy: Molecular design of spin qubits
2012
et al.
Exploiting Clock Transitions for the chemical design of resilient molecular spin qubits
2021
Molecular spin qubits are chemical nanoobjects with promising applications that are so far hampered by the rapid loss of quantum information, a process known as decoherence. A strategy to improve this situation involves employing so-called Clock Transitions (CTs), which arise at anticrossings between spin energy levels. At CTs, the spin states are protected from magnetic noise and present an enhanced quantum coherence. Unfortunately, these optimal points are intrinsically hard to control since their transition energy cannot be tuned by an external magnetic field; moreover, their resilience towards geometric distortions has not yet been analyzed. Here we employ a python-based computational t…
Direct Identification of Dilute Surface Spins on Al2O3 : Origin of Flux Noise in Quantum Circuits
2017
An on-chip electron spin resonance technique is applied to reveal the nature and origin of surface spins on Al2O3. We measure a spin density of 2.2×1017 spins/m2, attributed to physisorbed atomic hydrogen and S=1/2 electron spin states on the surface. This is direct evidence for the nature of spins responsible for flux noise in quantum circuits, which has been an issue of interest for several decades. Our findings open up a new approach to the identification and controlled reduction of paramagnetic sources of noise and decoherence in superconducting quantum devices.
Polymeric C3N4 and O-doped C3N4: Photoelectrochemical and EPR Features for Selective Photocatalytic Oxidation of Alcohols to Aldehydes
2018
Polymeric C3N4 and O-doped C3N4: Photoelectrochemical and EPR Features for Selective Photocatalytic Oxidation of Alcohols to Aldehydes
Refolding of the integral membrane protein light-harvesting complex II monitored by pulse EPR
2009
The major light-harvesting chlorophyll a / b complex (LHCII) of the photosynthetic apparatus in plants self-organizes in vitro. The recombinant apoprotein, denatured in dodecyl sulfate, spontaneously folds when it is mixed with its pigments, chlorophylls, and carotenoids in detergent solution, and assembles into structurally authentic LHCII in the course of several minutes. Pulse EPR techniques, specifically double-electron-electron resonance (DEER), have been used to analyze protein folding during this process. Pairs of nitroxide labels were introduced site-specifically into recombinant LHCII and shown not to affect the stability and function of the pigment-protein complex. Interspin dist…
Pulsed EPR analysis of tooth enamel samples exposed to UV and gamma-radiations
2011
Abstract The electron paramagnetic resonance (EPR) spectroscopy is widely applied for retrospective dosimetric purposes by means of quantitative detection of radicals in tooth enamel and bone samples. In this work we report a study by cw and pulsed EPR on two samples of human tooth enamel respectively irradiated by UV (254 nm) and γ-exposed. The continuous wave (cw) EPR spectra have shown the usual presence in both samples of two types of CO 2 − radicals, with axial and orthorombic g tensors. We have obtained the electron spin echo detected EPR (ED-EPR) spectra at 80 K of the two samples, and we have shown that they are suitable to mark the difference between the effects produced by the dif…
Analisi dei vetri di orologi tramite risonanza paramagnetica elettronica (EPR) e termoluminescenza (TL) per dosimetria retrospettiva
2016
Negli ultimi anni è cresciuto il rischio di esposizioni radiologiche non controllate della popolazione, sia a causa di incidenti associati ad applicazioni industriali e mediche delle radiazioni ionizzanti sia in seguito ad incidenti legati all’abbandono o alla dismissione di sorgenti ma anche ad un uso criminale di materiale radioattivo [1–3]. Gli effetti biologici prodotti dalle radiazioni ionizzanti dipendono fortemente dalla quantità di energia impartita per unità di massa (dose assorbita) [4]. Pertanto, nell’ambito di un incidente radiologico, disporre di procedure di ricostruzione della dose assorbita da un individuo può contribuire oltre che ad identificare i membri della popolazione …
New materials for ESR dosimetry in clinical photon and electron beams: Phenol Compounds.
2016
In the last decades several research laboratories have shown an increasing interest aimed at extending the applicability of ESR-dosimetry to radiotherapy with different types of radiation beams. ESR is a spectroscopic method for investigating the structure and dynamics of such paramagnetic species. The concentration of radiation-induced free radicals is proportional to the energy released inside in the medium. Our research group has started an investigation of the ESR response of some phenols compounds for possible ESR dosimetric applications suitable features, such as high efficiency of radiation-matter energy transfer and radical stability at room temperature. In particular, the phenoloct…