Nuclear quadrupole resonance
About: Nuclear quadrupole resonance is a(n) research topic. Over the lifetime, 3531 publication(s) have been published within this topic receiving 38801 citation(s). The topic is also known as: Nuclear quadrupole resonance spectroscopy & NQR.
Papers published on a yearly basis
01 Jan 1989
TL;DR: Vibronic interaction effects constitute a new field of investigation in the physics and chemistry of molecules and crystals that combines all the phenomena and laws originating from the mixing of different electronic states by nuclear displacements This field is based on a new concept which goes beyond the separate descriptions of electronic and nuclear motions in the adiabatic approximation as mentioned in this paper.
Abstract: Vibronic interaction effects constitute a new field of investigation in the physics and chemistry of molecules and crystals that combines all the phenomena and laws originating from the mixing of different electronic states by nuclear displacements This field is based on a new concept which goes beyond the separate descriptions of electronic and nuclear motions in the adiabatic approximation Publications on this topic often appear under the title of the lahn-Thller effect, although the area of application of the new approach is much wider: the term vibronic interaction seems to be more appropriate to the field as a whole The present understanding of the subject was reached only recently, during the last quarter of a century As a result of intensive development of the theory and experiment, it was shown that the nonadiabatic mixing of close-in-energy elec tronic states under nuclear displacements and the back influence of the modified electronic structure on the nuclear dynamics result in a series of new effects in the properties of molecules and crystals The applications of the theory of vibronic in of spectroscopy [including visible, ultraviolet, in teractions cover the full range frared, Raman, EPR, NMR, nuclear quadrupole resonance (NQR), nuclear gam ma resonance (NOR), photoelectron and x-ray spectroscopy], polarizability and magnetic susceptibility, scattering phenomena, ideal and impurity crystal physics and chemistry (including structural as well as ferroelectric phase transitions), stereochemistry and instability of molecular (including biological) systems, mechanisms of chemical reactions and catalysis"
01 May 1959-Physics Today
01 Aug 1979
TL;DR: In this article, the Mossbauer effect was used to measure the nuclear Gamma-Resonance (Mossbauer Spectrometer) of a single sample of a given sample.
Abstract: 1 Mossbauer (Nuclear Gamma-Resonance) Spectroscopy.- 1.1 Basic Principles and Experimental Arrangement.- 1.1.1 Isomer Nuclear Transitions and Gamma-Ray Emission.- 1.1.2 Resonance Fluorescence.- 1.1.3 Mossbauer Effect: a Recoilless Gamma-Fluorescence.- 1.1.4 Experimental Arrangement for Observing the Nuclear Gamma-Resonance (Mossbauer Spectrometer).- 1.1.5 Development of the Method.- 1.2 Mossbauers Nuclei.- 1.3 The Mossbauer Spectra Parameters.- 1.3.1 Isomer (Chemical) Shift.- 1.3.2 Quadrupole Splitting.- 1.3.3 Magnetic Hyperfine Structure.- 1.4 The Mossbauer Spectra of Minerals.- 1.4.1 Distribution of Fe2+ and Fe3+ in Rock-Forming Silicates.- 1.4.2 The Spectra of Sulfide Minerals.- 1.4.3 Spectra of Ferric Oxides and Hydroxides.- 1.4.4 Spectra of Iron in Different Classes of Minerals, in Meteorites, Tektites, and Lunar Samples.- 2 X-Ray and X-Ray Electron Spectroscopy.- 2.1 Basic Concepts.- 2.1.1 Development Stages.- 2.1.2 Systematics of X-Ray and X-Ray Electron Spectroscopy Types.- 2.1.3 X-Ray Emission Spectra.- 2.1.4 X-Ray Absorption Spectra. The Quantum Yield Spectra. Reflection Spectra. Isochromatic Spectra.- 2.1.5 X-Ray Electron Spectroscopy (Electron Spectroscopy for Chemical Analysis). Auger-Spectroscopy.- 2.2 Application of X-Ray and X-Ray Electron Spectroscopy to Study of Chemical Bonding in Minerals.- 2.2.1 Determination of Molecular Orbital and Energy Band Schemes from X-Ray and X-Ray Electron Spectra.- 2.2.2 Chemical Shifts in the X-Ray and X-Ray Electron Spectra and Determination of Effective Charges.- 3 Electron Paramagnetic Resonance.- 3.1 The Substance of the Electron Paramagnetic Resonance (EPR) Phenomenon.- 3.1.1 The Scheme of Obtaining EPR Spectra.- 3.1.2 The Energy Levels Scheme.- 3.1.3 Substances Which Can Be Investigated by Using EPR.- 3.1.4 EPR, Lasers, and Masers.- 3.2 Physical Meaning of the EPR Spectra Parameters.- 3.2.1 The Order of Measurements Experimental and Calculated Parameters.- 3.2.2 g-Factor and Splitting of the Spin Levels in a Magnetic Field.- 3.2.3 Fine Structure of the EPR Spectra Fine Structure Bmn (or D, E) Parameters Initial Splitting.- 3.2.4 Parameters of Hyperfine Structure. Interaction with Magnetic Nuclei of Paramagnetic Ions.- 3.2.5 Spin-Hamiltonian Order of Calculation the Paramagnetic Ions Spectra.- 3.3 Investigation of Minerals by EPR Spectra.- 3.3.1 Principal Applications of EPR Spectroscopy in Mineralogy and Geochemistry.- 3.3.2 Survey of EPR Data for Paramagnetic Impurity Ions in Minerals.- 4 Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR).- 4.1 The Principle of the Phenomenon and Types of Interaction in NMR.- 4.1.1 Types of Nuclei Viewed from the Standpoint of NMR.- 4.1.2 Two Types of NMR-Investigations.- 4.1.3 Principal Mechanisms of Interactions in NMR.- 4.1.4 Spectra of Nuclei with I = 1/2(H1, F19) in Solids.- 4.1.5 Spectra of Nuclei with I ? 1 in Solids.- 4.1.6 High-Resolution NMR-Spectroscopy in Solids.- 4.2 Nuclear Magnetic Resonance in Minerals.- 4.2.1 Types and Behavior of Water in Minerals Structural Position of Protons.- 4.2.2 Structural Applications of NMR.- 4.2.3 Experimental Estimations of the Crystal Field Gradient.- 4.3 Nuclear Quadrupole Resonance.- 4.3.1 The Energy Levels Diagram and the Resonance Condition in NQR.- 4.3.2 Quadrupole Nuclei and Requirements on the Study Substance.- 4.3.3 NQR Spectra Parameters.- 4.3.4 Minerals Investigated and Data Obtained.- 5 Luminescence.- 5.1 Major Steps in the Development and the Present-Day State.- 5.1.1 Applications of Luminescence in Mineralogy.- 5.1.2 Major Steps in the History of Luminescence.- 5.2 General Concepts, Elementary Processes, Parameters.- 5.2.1 Theoretical Bases Necessary for Understanding the Processes of Luminescence.- 5.2.2 Absorption, Luminescence, Excitation Spectra: the Scheme of the Experiment and Energy Levels.- 5.2.3 Energy Level Patterns and Configuration Curves Diagrams.- 5.2.4 Kinetics of Ion Luminescence in a Crystal Fluorescence and Phosphorescence.- 5.2.5 Transfer of Energy in Luminescence: Sensitization and Quenching.- 5.2.6 Representation of Luminescence in the Band Scheme and the Luminescence of Crystallophosphors.- 5.2.7 Methods of Luminescence Excitation.- 5.3 Types of Luminescent Systems in Minerals.- 5.3.1 Transition Metal Ions the Crystal Field Theory and Luminescence Spectra.- 5.3.2 Rare Earths Absorption and Luminescence Spectra.- 5.3.3 Actinides Absorption and Luminescence Spectra.- 5.3.4 Mercury-Like Ions Pb2+ in Feldspars and Calcites.- 5.3.5 Molecular Ions S?2 O?2 and F-Centers.- 5.3.6 Crystallophosphors of the ZnS Type Natural Sphalerites and Other Sulphides.- 5.3.7 Luminescence of Diamond.- 6 Thermoluminescence.- 6.1 Mechanism and Parameters of Thermoluminescence.- 6.1.1 The Nature of Emission Centers.- 6.1.2 The Nature of Trapping Centers.- 6.1.3 Determination of the Thermoluminescence Parameters.- 6.2 Experimental Data, Their Interpretation and Application in Geology.- 6.2.1 Alkali Halide Crystals.- 6.2.2 Fluorite.- 6.2.3 Anhydrite.- 6.2.4 Quartz.- 6.2.5 Feldspars.- 6.2.6 Calcite and Dolomite.- 6.2.7 Zircon.- 6.2.8 Geological Applications.- 6.2.9 Crystallochemical Factors.- 6.2.10 Physicochemical Factors.- 6.2.11 Geological and Geochemical Factors.- 6.2.12 Geological Age Dependences.- 7 Radiation Electron-Hole Centers (Free Radicals) in Minerals.- 7.1 Basic Principles and Methods.- 7.1.1 Discovery of Free Radicals in Minerals and Their Wide Distribution.- 7.1.2 Defects and Centers.- 7.1.3 Free Radicals in Crystals.- 7.1.4 Molecular Orbital Schemes and EPR Parameters.- 7.1.5 The Way to Identify the Electron-Hole Centers from the EPR Spectra.- 7.1.6 Systematics of the Electron-Hole Centers in Minerals and Inorganic Compounds.- 7.2 Description of the Centers.- 7.2.1 OxygenCenters: O?,O?2,O3?2,O?3.- 7.2.2 Carbonate Centers: CO3?3, CO?3, CO2.- 7.2.3 Sulfate and Sulfide Centers: SO?4, SO?3, SO?2 S?2 S?3.- 7.2.4 Silicate Centers: SiO5?4, SiO3?4, SiO?3, SiO?2.- 7.2.5 Phosphate Centers: PO4?4, PO2?4, PO2?3, PO2?2, PO02.- 7.2.6 Impurity Cation Centers.- 7.2.7 Hole Center S?.- 7.2.8 Atomic Hydrogen in Crystals.- 7.3 Models of Centers in Minerals.- 7.3.1 Prevalence and Significance of Centers in Minerals.- 7.3.2 Features Specific to the Structural Type and Models of the Centers in Minerals.- 7.3.3 Quartz.- 7.3.4 Feldspar.- 7.3.5 Framework Aluminosilicates with Additional Anions: Scapolite, Cancrinite, Sodalite, Ussingite Groups.- 7.3.6 Zeolites.- 7.3.7 Zircon.- 7.3.8 Beryl, Topaz, Phenakite, Euclase, Kyanite, Danburite, Datolite.- 7.3.9 Calcite.- 7.3.10 Anhydrite.- 7.3.11 Barite and Celestine.- 7.3.12 Apatite.- 7.3.13 Sheelite.- 7.3.14 Fluorite.- 7.4 Electron-Hole Centers in Alkali Halide Crystals.- 7.4.1 F Center.- 7.4.2 F Center in Compounds of Other Types.- 7.4.3 F Aggregate Centers.- 7.4.4 V Centers and Molecule Ions Hal?2, Hal3?2.- References.
01 Feb 1977-Physics Reports
TL;DR: In this paper, the double nuclear resonance techniques have been used for the detection of the nuclear quadrupole resonance (N.Q.R.) of many light elements which would have been impossible only a few years ago using conventional techniques.
Abstract: The development of double nuclear resonance techniques has allowed the detection of the nuclear quadrupole resonance (N.Q.R.) of many light elements which would have been impossible only a few years ago using conventional techniques. The apparatus is simple and easily automated and the methods yield good resolution combined with high sensitivity. Under the impact of these new techniques it appears likely that N.Q.R. will play a rapidly increasing role in the investigation of the internal electronic structure of solids. The various methods available are reviewed and those most suitable for N.Q.R., namely, Double Resonance in the Laboratory Frame (D.R.L.F.), Double Resonance by Level Crossing (D.R.L.C.), Double Resonance by Continuous Coupling (D.R.C.C.) and Double Resonance by the Solid State effect (D.R.S.S.) are examined in detail. The required theory is developed together with a description of experimental procedures and aids to the assignment of the spectra obtained. An apparatus suitable to employ the techniques is described. Listed in an appendix are the frequencies of the nuclear quadrupole resonance lines measured to date using the new techniques along with the deduced quadrupole coupling constants. Included are the spectra for over 200 different 14N sites, over different 2D sites together with some spectra of 10B, 11B, 17O, 23Na, 25Mg, 27Al and 39K.
01 Jun 1987-Physical Review Letters
TL;DR: Sample rotation is shown to induce frequency splittings in nuclear-quadrupole-resonance spectra, interpreted both as a manifestation of Berry's phase and as a result of a fictitious magnetic field, associated with a rotating-frame transformation.
Abstract: Sample rotation is shown to induce frequency splittings in nuclear-quadrupole-resonance spectra. The splittings are interpreted both as a manifestation of Berry's phase, associated with an adiabatically changing Hamiltonian, and as a result of a fictitious magnetic field, associated with a rotating-frame transformation. Real and fictitious fields are contrasted. Related effects are predicted in other magnetic resonance experiments that involve sample rotation.
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