What is the basic principle of nuclear quadrupole resonance?
The NQR resonance is mediated by the interaction of the electric field gradient (EFG) with the quadrupole moment of the nuclear charge distribution. Unlike NMR, NQR is applicable only to solids and not liquids, because in liquids the quadrupole moment averages out.
What is the application of nuclear quadrupole resonance?
Nuclear quadrupole resonance (NQR) spectroscopy provides information on the ground state charge distribution about a quadrupolar nucleus, because the NQR spectrum is determined by the components of the electric field gradient (EFG) tensor.
What is the principle of NQR spectroscopy?
NQR is a method based on the resonance absorption of electromagnetic energy in a substance owing to quantum transitions between nuclear energy levels, created by a nuclear quadrupole moment interaction with the gradient of the intracrystal electric field (Section 8.2. 4, Figure 8.2c).
What is a nuclear quadrupole resonance sensor?
Nuclear quadrupole resonance (NQR) is a spectroscopic technique that can detect explosives of high. chemical specificity and therefore it is very suitable for the landmine detection problem.
What is nuclear quadrupole moment?
The quadrupole moment of a nucleus is usually defined1 as “the quantity (3z2 — r2)Av, where the average is taken over the nuclear charges for the state which has the maximum component of spin I in the z direction”.
What do you mean by electric quadrupole?
[i¦lek·trik ′kwä·drə‚pōl] (electricity) A charge distribution that produces an electric field equivalent to that produced by two electric dipoles whose dipole moments have the same magnitude but point in opposite directions and which are separated from each other by a small distance.
What is meant by the quadrupole moment of a Nucleous What information do you get from it about the charge distribution of nucleus?
The nuclear electric quadrupole moment is a parameter which describes the effective shape of the ellipsoid of nuclear charge distribution. The quantity Q0 is the classical form of the calculation represents the departure from spherical symmetry in the rest frame of the nucleus.
What are limitations of NQR spectroscopy?
The principal disadvantage of NQR, other than sensitivity, is that, as a radiofrequency (RF) technique, it is incompatible with conducting or ferromagnetic materials; however, for the somewhat narrow range of materials to which it can be applied, NQR gives information which is otherwise unavailable.
What does quadrupole mean?
Definition of quadrupole : a system composed of two dipoles of equal but oppositely directed moment.
What is the significance of quadrupole moment?
The nuclear electric quadrupole moment gives a measure of the deviation of the nucleus, or more precisely of its charge distribution, from a spherical shape and hence is an important source of information about nuclear structure.
Why is quadrupole called quadrupole?
As the name implies, it consists of four cylindrical rods, set parallel to each other. In a quadrupole mass spectrometer the quadrupole is the mass analyzer – the component of the instrument responsible for selecting sample ions based on their mass-to-charge ratio (m/z).
What is quadrupole effect?
A quadrupolar nucleus is one that has a quantum spin number greater than ½. Such nuclei have a lower symmetry than spin-½ nuclei. The quadrupole moment that varies between nuclei is a measure of this asymmetry. Their energies split upon the application of a magnetic field into multiple levels (fig. 1).