Nuclear quadrupole resonance spectroscopy

The 3 C1 n.q.r. spectrum of COClj at 77 K has been measured it shows two lines (at 36.225 and 35.081 MHz) [1262], and an attempt to predict these frequencies by a modified CNDO method led to a 4.63% overestimate [400]. It should be noted that the lower frequency resonance was misquoted as 35.001 MHz by Cohen and Whitehead [400], and 

For a wide range of chlorine-containing compounds, a correlation was found between the 5 5C1 n.q.r. frequencies and the Taft inductive effects of the other substituents (where known) [199,1611,1838]. Phosgene is the first member (n = 0) of the homologous series, C1(CH j) C(0)Cl, which has also been investigated for regular trends in n.q.r. frequency [648], 

The normal format is followed in the more detailed sections, with results for main group elements preceding those for transition metals and lanthanides. 

1 Group 13 (Alumininm-27, Gallium-69 and -71, and Indinm-115). - A theoretical analysis of the electronic structures of dimeric compounds A Xe (X = F, 

Spectroscopic Properties of Inorganic and Organometallic Compounds, Volume 35 The Royal Society of Chemistry, 2002 

04 T 100 K, the SLR showed a strong T-dependence, indicating that the compound was much more itinerant than previously known Ce-based HF compounds. The observed T-variation was considered to indicate anisotropic spin fluctuations near a magnetic ordering, arising from a layered crystal structure. Bulk superconductivity set in at 0.40 K, below which there was no coherence peak and the SLR followed a relationship, suggesting unconventional superconductivity with an anisotropic (line-node) energy gap. 

Ti values for Sb nuclei in SbCfi have been measured from 4.2 K to the 

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T. P. Das and E. L. Hahn, Nuclear Quadrupole Resonance Spectroscopy, Academic Press, New York, 1958, 223 pp E. A. C. Lucken, Nuclear Quadrupole Coupling Constants, Academic Press, London, 1969, 360 pp. 

Nuclear Magnetic Resonance and Nuclear Quadrupole Resonance Spectroscopy.59... 

A parameter, 17, used for describing nonsymmetric fields in nuclear quadrupole resonance spectroscopy. It is defined as 17 = ( xx field gradient q (which is the second derivative of the time-averaged electric potential) along the x-, y- and z-axes. By convention, refers to the largest field gradient, q-yy to the next largest, and q to the smallest when all three values are different. 

Nuclear quadrupole resonance spectroscopy, see also specific compounds cyclophosphazenes, 21 93 of subvalent compounds, 29 298, 308-309 transition metal nitrosyl complexes, 34 313-314... 

Another important nuclear characteristic is the nuclear quadrupole moment which, possessed by nuclei for which 7 1, has given rise to the important field of nuclear quadrupole resonance spectroscopy. A major importance of the quadrupole moment with respect to NMR absorption resides in the effects of quadrupole coupling constants on nuclear relaxation times and, therefore, on the line widths and saturation characteristics of NMR absorption (9). In addition, in favorable situations, quadrupole coupling constants can be derived from the characteristics of nuclear resonance of quadrupolar nuclei 127). Some examples of these effects will be described in Sections III, IV and VI of this chapter. 

Often, these adducts were characterized by vibrational spectroscopy, and Raman spectroscopic investigations were particularly informative and indicative for the occurrence of E E bonds. Some E E stretching vibrations vE E are summarized in Table I. They nicely show the expected dependency of vE E on the atomic masses of the respective elements and on the masses of the substituents. Some compounds were further characterized by nuclear quadrupole resonance spectroscopy, which gave indications for phase transfer processes and for the extent of electron transfer from the ligands to Ga or In atoms.15,16 Most helpful for the discussion of the constitution and conformation of these subhalides are the results of X-ray... 

T. P. Das and E. L. Hahn, Nuclear Quadrupole Resonance Spectroscopy, Academic Press, New York (1958). 

G. A. Barrall, L. J. Burnett, and A. G. Shelton, Method and System for Cancellation of Extraneous Signals in Nuclear Quadrupole Resonance Spectroscopy, US Patent No. 6 392 408 (2002). 

The third problem also concerns the choice of whether to leave out certain material. In a book of this size it is not possible to cover all branches of spectroscopy. Such decisions are difficult ones but I have chosen not to include spin resonance spectroscopy (NMR and ESR), nuclear quadrupole resonance spectroscopy (NQR), and Mossbauer spectroscopy. The exclusion of these areas, which have been well covered in other texts, has been caused, I suppose, by the inclusion, in Chapter 8, of photoelectron spectroscopy (ultraviolet and X-ray), Auger electron spectroscopy, and extended X-ray absorption fine structure, including applications to studies of solid surfaces, and, in Chapter 9, the theory and some examples of lasers and some of their uses in spectroscopy. Most of the material in these two chapters will not be found in comparable texts but is of very great importance in spectroscopy today. 

Nuclear quadrupole resonance spectroscopy (NQR) is a very direct and experimentally quite simple method for studying the interaction between the electric quadrupole moment of a nucleus and the electric field gradient at its site. Since the discovery of the method by Dehmelt and Kruger 3>6) in 1950, a large amount of experimental material has been collected, most of which has been interpreted within the frame of semiempirical theories. 

There are several papers and books 3-5> devoted to nuclear quadrupole resonance spectroscopy however, we think it better to begin with a brief survey of some of the theoretical aspects of pure quadrupole resonance for a spin I = 1, as well as of the experimental apparatus, before dealing with the detailed sxudy of nitrogen resonances. 

O Konski, C.T. Nuclear Quadrupole Resonance Spectroscopy. In Determination of Organic Structure by Physical Methods (ed. F.C. Nachod, W.D. Phillips). 

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