نتایج جستجو برای: nuclear quadrupole resonance nqr

تعداد نتایج: 438028  

2012
Jose A. Abanero

Z. Naturforsch. 45a, 353-356 (1990); received August 25, 1989 The 1 N nuclear quadrupole resonance (NQR) of the cyanides in Ba[Fe(CN)sNO] • 3 H 2 0 (BNP) was observed between 77 and 293 K. Phase transitions exist at 118,131 (both weakly first order) and 233 K (second order). Most of the cyanides were perturbed by the structural changes except for one of the trans cyanides that was only affected...

2016
Yuji Furukawa B. Roy Sergey L. Bud'ko Paul C. Canfield P. C. Canfield

The static and the dynamic spin correlations in the low-temperature collapsed tetragonal and the hightemperature tetragonal phase in CaFe2As2 have been investigated by As75 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. Through the temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts, although stripe-type ant...

2012
V. S. Grechishkin

Direct NQR signals from the light nuclei H, B, N use to be weak; their detection is difficult. For these light nuclei nuclear quadrupole double resonance (DNQR) methods are preferable in which the sensitivity is enhanced due to the thermal contact of two spin-systems and indirect detection. The higher the initial magnetic field B0, the better is the DNQR sensitivity. Apart from this, the DNQR s...

2011
Cory M. Widdifield Alex D. Bain David L. Bryce

Solid-state 185/187 Re NMR spectral evidence for the origin of high-order quadrupole-induced eff ects HOT ARTICLE Dolnik et al. Locking of Turing patterns in the chlorine dioxide–iodine–malonic acid reaction Definitive solid-state 185/187 Re NMR spectral evidence for and analysis of the origin of high-order quadrupole-induced effects for I = 5/2w Rhenium-185/187 solid-state nuclear magnetic res...

1999
P. F. Meier

The nuclear quadrupole resonance (NQR) spectrum of strontium doped La2CuO4 surprisingly resembles the NQR spectrum of La2CuO4 doped with excess oxygen, both spectra being dominated by a main peak and one principal satellite peak at similar frequencies. Using first-principles cluster calculations this is investigated here by calculating the electric field gradient (EFG) at the central copper sit...

2018
Paul W. Wiecki V. Taufour D. Y. Chung M. G. Kanatzidis Sergey Bud’ko

We present the results of 75 As nuclear magnetic resonance (NMR), nuclear quadrupole resonance (NQR), and resistivity measurements in KFe 2 As 2 under pressure ( p ). The temperature dependence of the NMR shift, nuclear spin-lattice relaxation time ( T 1 ), and resistivity show a crossover between a high-temperature incoherent, local-moment behavior and a low-temperature coherent behavior at a ...

Journal: :npj quantum materials 2022

Abstract A V 3 Sb 5 ( = K, Rb, Cs) is a novel kagome superconductor coexisting with the charge density wave (CDW) order. Identifying structure of CDW order crucial for understanding exotic normal state and superconductivity in this system. Here, we report 51 nuclear magnetic resonance (NMR) 121/123 quadrupole (NQR) studies on kagome-metal CsV . Below transition temperature T ~ 98 an abrupt chan...

2008
E. Mammadov P. C. Taylor

The local bonding structure in the Ge–As–Se ternary glassy system has been investigated by As nuclear quadrupole resonance (NQR) at 77 K. For the compositions with average coordination number r 1⁄4 2:2; 2:4; 2:54 the NQR measurements yield no evidence for the presence of As–As homopolar bonds. For the composition Ge2As2Se5 ( r 1⁄4 2:67) the NQR lineshape exhibits two peaks corresponding to arse...

Journal: :Analytical chemistry 2015
Georgia Kyriakidou Andreas Jakobsson Kaspar Althoefer Jamie Barras

In this paper, we report on the identification of batches of analgesic paracetamol (acetaminophen) tablets using nitrogen-14 nuclear quadrupole resonance spectroscopy ((14)N NQR). The high sensitivity of NQR to the electron charge distribution surrounding the quadrupolar nucleus enables the unique characterization of the crystal structure of the material. Two hypothesis were tested on batches o...

Nuclear quadrupole resonance (NQR) spectroscopy is an accurate method for determination of electric charge distribution around quadrupolar nuclei. Using ab initio computational methods, it is possible to calculate the Nuclear Quadrupole Coupling Constants (NQCCs) with high accuracy and obtain the useful structural information by using these parameters. Sodium Borohydride, NaBH4, is a metal hydr...

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