Topic
Nuclear quadrupole resonance
About: Nuclear quadrupole resonance is a research topic. Over the lifetime, 3531 publications have been published within this topic receiving 38801 citations. The topic is also known as: Nuclear quadrupole resonance spectroscopy & NQR.
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TL;DR: Theoretical expression for the Hamiltonian of the electron coupled interaction between two nuclei in an iodine molecule is derived, having the form of J I A z I B z + K (I A x I B x + I A y I B y ), where z is the bond axis.
Abstract: Hyperfine structure in the nuclear quadrupole resonance spectrum of solid iodine observed by Kojima, Ogawa, Hagiwara, Abe and Minematsu is analysed in terms of electron coupled interaction between nuclear spins. Theoretical expression for the Hamiltonian of the electron coupled interaction between two nuclei in an iodine molecule is derived, having the form of J I A z I B z + K ( I A x I B x + I A y I B y ), where z is the bond axis. Electron coupled interactions between nuclei belonging to different molecules in the crystal are neglected. Values of the coupling constants J and K are determined to be both equal to 3.0 kc from the comparison with the experimental data. Electronic structure of the chemical bond is discussed on the basis of the above coupling constants in combination with the previously known quadrupole coupling constants. It is concluded that the bond in an iodine molecule has 22% s character and 33% d character. It is also concluded that there are auxiliary bonds between neighboring molecu...
16 citations
16 citations
TL;DR: In this article, an electron-doped LaFeAsO 1-x F x (La1111) with T c = 5 K was studied and the sign reversal of the gap functions on different FSs is realized in La1111 compounds.
Abstract: We report an 75 As-nuclear quadrupole resonance (NQR) study on heavily electron-doped LaFeAsO 1- x F x (La1111) with T c =5 K. The measurement of the nuclear spin relaxation rate (1/ T 1 ) has revealed that a Hebel–Slichter (HS) peak partially recovers in heavily electron-overdoped regimes where the nesting condition of hole and electron Fermi surfaces (FSs) becomes significantly worse. This is in contrast to previous results reported for optimally doped La1111 with T c =28 K that there is a lack of the HS peak. These results indicate that the interband scattering between the hole and electron FSs is strongly suppressed by an almost vanishing hole FS because of the heavy electron-overdoping. Our findings strongly suggest that the sign reversal of the gap functions on different FSs, that is, the s ± -wave state, is realized in La1111 compounds. We remark that interband scattering on well-nested FSs is essential for stabilizing the s ± -wave state and enhancing T c up to 28 K in LaFeAsO-based superconductors.
16 citations
University of the Witwatersrand1, Botswana International University of Science and Technology2, University of Cape Town3, Joint Institute for Nuclear Research4, Dresden University of Technology5, Technische Universität Darmstadt6, Charles University in Prague7, Stellenbosch University8, Osaka University9
TL;DR: The fine structure of the Isoscalar giant quadrupole resonance (ISGQR) has been studied with high energy-resolution proton inelastic scattering at iThemba LABS in the chain of stable even-mass Nd isotopes covering the transition from spherical to deformed ground states as discussed by the authors.
16 citations
TL;DR: In this article, the 11B and 10B nuclear quadrupole resonance spectra of boric acid have been obtained at 77 K, by means of the technique of double resonance by level crossing.
16 citations