May 16, 2008 the detection of explosives is a challenging topic. The nuclei that show nqr spectra are listed and the appearance of the spectra is explained for different spin quantum numbers. Feasibility of nuclear quadrupole resonance as a technique. Simulation of nuclear quadrupole resonance for sensor probe optimization. Electric field gradient nuclear quadrupole resonance double resonance nitrogen mustard asymmetry factor these keywords were added by machine and not by the authors. This absorption is due to reorientation of the nonspherical atomic nuclei against crystalline electric fields.
Nuclear quadrupole resonance nqr is the study of the energy splittings due to interaction of the electric quadrupole moment of the nucleus with the electric field gradient that exists at the nuclear site. Basic principles and their applications 233 to observe a nuclear magnetic absorption, we have to adjust either the frequency. Daniel canet, lionel merlat, benoit cordier, denis grandclaude, alain retournard, maude ferrari. The sample is placed in a magnetic field and the nmr signal is produced by excitation of the nuclei sample with radio waves into nuclear magnetic resonance. The theory of nuclear quadrupole resonance spectroscopy is summarized. As far back as the 1950s, studies were performed in crystals both in the regime where the nuclear quadrupole interaction caused weak perturbations to the nuclear magnetic resonance nmr the nqr lines could be clearly resolved by using highlyspectra 1, as well as in the pure. View nuclear quadrupole resonance research papers on academia. When the magnetic and quadrupolar interactions are of comparable size, perturbation.
Temperature effects in nuclear quadrupole resonance. Nqr is a particular case of nuclear magnetic resonance nmr in crystals. Symmetry constraints on nuclear quadrupole resonance. It determines the physical and chemical properties of atoms or the molecules.
The application of nmr spectroscopy to the study of proteins and nucleic acids has provided unique information on the dynamics and chemical kinetics of these systems. Naval research laboratory nrl has expertise in solid state nuclear magnetic resonance nmr, magnetic resonance imaging mri. Nuclear quadrupole resonance nqr article about nuclear. Bloch and purcell shared the nobel prize for physics in 1952. Nuclear magnetic resonance nmr is a spectroscopic technique that detects the energy absorbed by changes in the nuclear spin state. Hyperfine interaction and nuclear quadrupole resonance nuclear quadrupole resonance nqr to nuclear quadrupole interaction nqi. High sensitivity nuclear quadrupole resonance of light nuclei. As the central lines of the two crystals remain at w. Nuclear quadrupole resonance spectroscopy or nqr is a chemical analysis technique related to nuclear magnetic resonance. Hibbs, quantum magnetics introduction nuclear quadrupole resonance nqr combines the spatial localization capability and convenience of metal detection or groundpenetrating radar gpr with the compound specific detection capability offered by chemical detection techniques. Pdf nuclear quadrupole resonance for explosive detection.
Nutation spectra of nuclear quadrupole resonance in off. Characterization of zeolites and amorphous silicaaluminas. Nuclear quadrupole resonance nqr is a spectroscopic technique that can detect explosives with high chemical specificity and therefore it is very suitable for the landmine detection problem. The resonance effect comes from the fact that valence electrons preferentially align with some of the 14 n. The institute of medical engineering, beside coordination, is responsible for two tasks. However, despite the great similarities between nmr and nuclear quadrupole resonance nqr, no experimental implementation for qip using nqr has been reported. Nuclear quadrupole resonance nqr spectroscopy provides a sensitive means to detect these. Nuclear quadrupole resonance for explosive detection. Nuclear magnetic resonance spectroscopynmr is a powerful analytical technique used to characterize organic molecules by identifying carbonhydrogen frameworks within molecules. Locked nuclear quadrupole resonance spectrometer for pressure measurements ronald c. A selective absorption phenomenon observable in a wide variety of polycrystalline compounds containing nonspherical atomic nuclei when placed in a ma.
Nuclear m agnetic resonance sp ectroscopy nuc lear quadrupole resonance applications theory offered townes and dailey. Nuclear quadrupole resonance nqr is a radio frequency rf spectroscopy technique for solid materials the instrumentation is like nmr but nqr doesnt require an applied b 0 field because the physical mechanism is different there are benefits. This moment is a measure of how the nuclear charge distribution deviates away from spherical symmetry and it happens in nuclei with greater spin or equal to. Application of nuclear quadrupole resonance to detection of explosives and research activities at ciae shengyun zhu, xing li, zhongcheng lu, guobao wang, and weiguo shu china institute of atomic energy p. Nuclear magnetic resonance nmr is a method of physical observation in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field in the near field and therefore not involving electromagnetic waves and respond by producing an electromagnetic signal with a frequency characteristic of the magnetic field at the nucleus. Nuclear magnetic resonance electric field gradient nuclear quadrupole resonance quadrupole coupling constant electric quadrupole moment these keywords were added by machine and not by the authors. Quadrupole couplings in nuclear magnetic resonance, general. Utilization of pure nuclear quadrupole resonance spectroscopy for the study of pharmaceutical crystal forms. We trace the transformation of i 32 1xe nuclear spin resonances from the pure nuclear quadrupole regime to the quadrupoleperturbed zeeman regime. Explosives detection with nuclear quadrupole resonance.
In the simplest case, for example, 35cl in solid cl 2, nqr is associated with the precession of the angular. Nuclear magnetic resonance detection and spectroscopy of. Nuclear magnetic resonance, first demonstrated in 1946, takes advantage of the fact that certain atomic nuclei possess magnetic dipole moments. Nuclear magnetic resonance spectroscopy with single spin. Some examples of nuclear quadrupole moments nucleus i q 1028m2 2h 1 2. They demonstrated the magnetic resonance detection and spectroscopy of. George mason university, 2010 dissertation director.
A technique, allied to nuclear magnetic resonance, that has a number of academic and practical applications nuclear quadrupole resonance meaning. In this chapter, the basic principles and concepts of nmr spectroscopy are described. The nuclear quadrupole resonance nqr frequency of chlorine atoms in the quantum organic magnet dichloro tetrakisthiourea nickel dtn, with chemical formula nicl 2 4scnh 2 2, is a physical characteristic that can be used to study its fine structure. Video shows what nuclear quadrupole resonance means. Symmetry constraints on nuclear quadrupole resonance spectra. Information and translations of nuclear quadrupole resonance in the most comprehensive dictionary definitions resource on the web. Nuclear quadrupole resonance for explosive detection hideo itozaki and go ota graduate school of engineering science, osaka university machikaneyama toyonaka, osaka, 5608531, japan abstract abstract a nuclear quadrupole resonance detector has been developed. Suits physics department, michigan technological university, houghton, mi, usa 2. Dependence on the detuning df of the nqr nutation spectrum obtained via a synchronized. Nuclear quadrupole resonance at the naval research laboratory the polymer diagnostics section code 6122 of the u. This discovery, known as nuclear magnetic resonance, and the experimental techniques that have developed, are applied in many different scientific fields. It is a research technique that exploits the magnetic properties of certain atomic nuclei.
Related phenomena in isolated molecules are briefly mentioned in the introduction a. The peak value of the output signal is s it 0, which yields for all ith components a complete energy spectrum. Nuclear quadrupole resonance article about nuclear. Nuclei with a spin greater than 12, such as 14 n, have a nuclear electric quadrupole moment that interacts with the electric field of the surrounding electrons, producing an electric quadrupole coupling. Armstrong department of physics university of toronto toronto, canada mss1a7 many crystals undergo one or more structural phase changes as their temperature is lowered. The first two arise, respectively, from the interaction of the magnetic moment of a nucleus or an electron with an external magnetic field.
Nqr is a spectroscopy technique very similar to nuclear magnetic resonance, which exploits the fact that some nuclei possess electric quadrupole moment. Pdf utilization of pure nuclear quadrupole resonance. Vanderhart institute for materials research, national bureau of standards, washington, d. Nuclear magnetic resonance nmr spectroscopy direct observation of the hs and cs of a molecules nuclei are positively charged and spin on an axis. Nuclear quadrupole resonance research papers academia. Appendix j nuclear quadrupole resonance paper i andrew d. Unlike nmr, nqr transitions of nuclei can be detected in the absence of a magnetic field, and for this reason nqr spectroscopy is referred to as zero field nmr. The nucleus can be regarded as a rigid particle with a definite magnetic dipole moment and electric quadrupole moment. Nuclear magnetic resonance spectroscopy is a powerful technique that can identify the presence of certain atoms in a sample by their magnetic properties. We achieve large nuclear quadrupole shifts by using a 1mm 3 cubic cell with walls of different materials.
The following chapters give a short overview about the. Chapter 2 nuclear quadrupole resonance spectroscopy bryan h. The nqr resonance is mediated by the interaction of the electric field gradient efg with the quadrupole. Nuclear magnetic resonance nmr has been widely used in the context of quantum information processing qip. Nuclear magnetic resonance spectroscopy, most commonly known as nmr spectroscopy or magnetic resonance spectroscopy mrs, is a spectroscopic technique to observe local magnetic fields around atomic nuclei. Hyperfine interaction and nuclear quadrupole resonance. Unit iii nuclear quadrupole resonance spectroscopy basic. The gradient of an electrical field in a place of a presence. Nuclear quadrupole resonance detection of explosives. Sauer nuclear quadrupole resonance nqr is a type of radiofrequency rf spectroscopy. Introduction the development of nuclear magnetic resonance spectroscopy sub sequent to the initial discoveries by purcell and bloch in 1946 is now recognized as one of the most important events in the last fifty years for the advancement of organic chemistry. Nuclear quadrupole resonance has much in common with nuclear magnetic resonance nmr, the fundamental physical process that makes magnetic resonance imaging possible. Many nuclei with spins greater than vz have a quadrupole moment and most of these quadrupole moments have been measured and tabulated.
Nuclear quadrupole resonance is a recently developed branch of radiofrequency spectroscopy which is concerned with magnetic resonance absorption in crystals. Nuclear magnetic resonance is a powerful technique for medical imaging and the structural analysis of materials, but is usually associated with largevolume samples. This was a consequence of the growing number of scientists using nuclear methods to study quadrupole coupling in condensed matter. Nuclear quadrupole resonance nqr is a radio frequency rf spectroscopy technique for solid materials the instrumentation is like nmr but nqr doesnt require an applied b 0 field because the physical mechanism is different there are benefits and drawbacks to nqr as compared with nmr. Application of nuclear quadrupole resonance to detection. Nmr is the most powerful method for the identification of organic compounds, and is widely applied in many fields. Locked nuclear quadrupole resonance spectrometer for. Other articles where nuclear quadrupole reaction spectroscopy is discussed. Effect of a single radiofrequency pulse in the general case. Nuclear quadrupole resonance nqr the resonance absorption of electromagnetic energy in a crystal owing to transitions between energy levels that are formed as a result of the interaction of nuclei that have an electric quadrupole moment with the crystal electric field. Basic concepts of nqr nuclear electric quadrupole moment, electric field gradient, energy levels and nqr frequencies, effect of magnetic field on spectra, factors affecting the resonance signal line shape, position of resonance signal relationship between electric field gradient and molecular structure. This process is experimental and the keywords may be updated as the learning algorithm improves. Definition of nuclear quadrupole resonance in the definitions.
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