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Free induction emission

This emission is referred to as free induction emission. It is a coherent emission. [Pg.517]

Figure 4. Coherent transients observed in gases and molecular beams. Shown are the photon echo (detected by spontaneous emission), the free induction decay, and Ti for different pressures (iodine gas and beam). Figure 4. Coherent transients observed in gases and molecular beams. Shown are the photon echo (detected by spontaneous emission), the free induction decay, and Ti for different pressures (iodine gas and beam).
Modern instruments are Fourier transform NMR, which use a constant magnetic field commonly produced by a superconducting magnet and a strong radio-frequency pulse that irradiates the sample. The free induction decay signal emission of the sample is... [Pg.192]

The end result of an NMR experiment is the emission signal, which is detected and recorded as a free-induction decay, or FID (Fig. 2.3d). A free-induction decay is a time-domain signal, because it is recorded as a function of intensity over time. The trans-... [Pg.30]

FID free induction decay PET positron emission tomography... [Pg.419]

So the first example of real superradiance was in fact the free induction decay and die decay of the photon echo observed in ruby by Kumit, Abella and Hartmann (1964). When a pulse from a ruby laser was sent onto a ruby crystal, the free induction decay and the echo decay observed were about 50 ns, when compared to the usual Cr " radiative decay time of 4 ms, showing clearly the radiation emission from the macro-dipole. [Pg.526]

Superfluorescence (SF) in the solid state and in R ions. Because even the radiation damping of the free induction decay in ruby (Kumit et al. 1964), has been questioned as being SR and reinterpreted as a superfluorescence emission (Polder et al. 1979), SF seems easier to observe, so let us review the situation in R-doped systems. [Pg.531]

Since the molecule contains many different nuclei, many different frequencies of electromagnetic radiation are emitted simultaneously. This emission is called a free-induction decay (FID) signal (Fig. 5.15). Notice that the intaisity of the FID decays with time as all of Ihe nuclei eventually lose Iheir excitation. The FID is a superimposed combination of all the frequencies emitted and can be quite complex. We usually extract the individual fiequencies due to different nuclei by using a computer and a mathematical method called a Fourier transform (FT) analysis, which is described later in this section. [Pg.227]

A binder—free Na-Y zeolite with Si/Al ratio of 2.29 was obtained from Strem Chemical Co., La,Na—Y and Cs,Na-Y zeolites were prepared by exchanging Na-Y zeolite with LaCls and CsCl solution at room temperature. The percentage of metal ion exchanged in a zeolite has been determinated by Inductively-Coupled-Plasma Atomic Emission Spectroscopy and the number is used as prefix for the samples, e.g., Cs exchanged level of 667. is represented as 66Cs,Na-Y sample. [Pg.124]

Flame AAS (often abbreviated FAAS) was until recently the most widely used method for trace metal analysis. However, it has now largely been superseded by inductively coupled plasma atomic emission spectrometry (see Chapter 4). It is particularly applicable where the sample is in solution or readily solubilized. It is very simple to use and, as we shall see, remarkably free from interferences. Its growth in popularity has been so rapid that on two occasions, the mid-1960s and the early 1970s, the growth in sales of atomic absorption instruments has exceeded that necessary to ensure that the whole face of the globe would be covered by atomic absorption instruments before the end of the century. [Pg.15]

An inductively coupled argon plasma eliminates many common interferences. The plasma is twice as hot as a conventional flame, and the residence time of analyte in the flame is about twice as long. Therefore, atomization is more complete and signal is enhanced. Formation of analyte oxides and hydroxides is negligible. The plasma is remarkably free of background radiation 15-35 mm above the load coil where sample emission is observed. [Pg.468]

Stefansson, A., I. Gunnarsson, and N. Giroud. 2007. New methods for the direct determination of dissolved inorganic, organic and total carbon in natural waters by reagent-free ion chromatography and inductively coupled plasma atomic emission spectrometry. Anal. Chim. Acta 582 69-74. [Pg.239]

New methodologies for the laboratory analysis of cations and metals include the use of inductively coupled plasma emission spectrometry (ICP/ES) or the combinahon of ICP with mass spectrometry (ICP/MS) (e.g., Ivahnenko et al., 2001). The advantages of plasma techniques include (i) a wide and linear dynamic concen-trahon range (ii) multi-element capabihty and (iii) relatively free of matrix interferences. The use of ion chromatography (1C), gas chromatography (GC), and GC/MS has increased for the analysis of anions and dissolved organics (Barth, 1987 Kharaka and Thordsen, 1992 Ivahnenko et al., 2001). [Pg.2754]

For ICP-OES-MS (inductively coupled plasma-optical emission spectroscopy-mass spectroscopy) work, the desolvator will remove oxide and hydride polyatomic ion interferences, i.e. ArO+ is reduced 100 fold, which allows for improved detection of Fe. The solvent loading reduction is caused by volatiles passing through the walls of a tubular microporous Teflon PTFE membrane. The argon gas removes the solvent vapour from the exterior of the membrane. Solvent-free analytes remain inside the membrane and are carried to the plasma for atomisation and excitation. [Pg.39]

Knowledge of the atomic spectra is also very important so as to be able to select interference-free analysis lines for a given element in a well-defined matrix at a certain concentration level. To do this, wavelength atlases or spectral cards for the different sources can be used, as they have been published for arcs and sparks, glow discharges and inductively coupled plasma atomic emission spectrometry (see earlier). In the case of ICP-OES, for example, an atlas with spectral scans around a large number of prominent analytical lines [329] is available, as well as tables with normalized intensities and critical concentrations for atomic emission spectrometers with different spectral bandwidths for a large number of these measured ICP line intensities, and also for intensities calculated from arc and spark tables [334]. The problem of the selection of interference-free lines in any case is much more complex than in AAS or AFS work. [Pg.202]

McKinnon P. W., Giess K. C. and Knight T. V. (1981) A clog-free nebulizer for use in inductively coupled plasma-atomic emission spectroscopy, in Barnes R. M. (ed) Developments in atomic plasma spectrochemical analysis. Heyden, London, 287-301. [Pg.321]


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Free induction

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