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chemistry assignments, Neutron diffraction supplements x-ray diffraction and is particularly helpful in locating hydrogen atoms.An x-ray beam is scattered primarily as a result of interaction with the electrons that surround each atom of an ion or molecule. Thus the atomic scattering factors are approximately proportional to atomic numbers. As a result, it is difficult to locate low atomic number in the presence of high atomic number atoms. Thus the position of hydrogen atoms generally cannot be deduced from x-ray diffraction studies. (A positive attitude to this difficulty is the recognition add to the complexity of many already complex structure determinations.) Within a factor of 3 or 4, all nuclei or, more conveniently, deuterium nuclei can be located in the presence fo behavior atoms.Neutron diffraction is also distinguished by the noticeable role of the magnetic moment of the neutron when diffraction occurs from crystals with ordered atomic magnetic moments. Neutrons diffraction can be used to study the orientation of atomic magnetic moments in ferromagnetic and antiferromagnetic crystals. Neutron diffraction is thus a specialized adjunct to z-ray diffraction.A neutron beam is usually formed from the thermal neutrons of a nuclear reactor. A velocity selector device augmented by crystal diffraction provides a monochromatic beam. The wavelength associated with the neutron beam can be calculated from the de Broglie relation. The momentum term mv is obtained for thermal neutrons by setting½ mv2 = 3/2 kTAnd rearranging to get;Mv = √3mkTWith appropriate numerical values, including 1.675 × 10-27 kg for the mass of a neutron, we obtain,1.46 ×10-10 m = 146 pmA beam of thermal neutrons therefore has a wavelength suitable for diffraction studies of crystals. A diffraction pattern like those obtained for x-ray diffraction except that a longer wavelength beam is used is obtained.Typically crystals, whose structures are known, except for the postions of hydrogen atoms, are studied. The transform procedure is used that the positions fo these remaining nuclei are found. The smallness of the nuclei would lead to sharp peaks on a nuclear density map, but thermal motion produces some spreading of these peaks.
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if marginal cost descreases then what else is effected by this
Economies of Scope The ability of a organization to decrease its unit costs by producing two or more products or services that involve complementary skills, experience and
P=140-4Q mc1=20+30q for plant 1 mc2=80+10q for plant 2 how many units should be produced by plant 1 and plant 2 to maximise profit for this monopoly?
1. Igora's pizzeria want to know if it should stay open this spring. Total Revenue will be $ 12,000 per week and Total Cost will be $ 18,000 per week. The fixed cost of running the
What are the advantages of leaving the allocation of a countrys resources to the price mechanism? Ans) The main conditions needed are: 1. Either a finite number of agents or pr
STETE THE THEORIES OF DETERMINATION OF RENT
Change in the population of consumers: Population changes may affect the demand for a commodity.Areas of high population may demand more of certain commodities than areas of low
chemistry assignments , Some normally nonmagnetic substances are attracted by a magnetic field and studies of these "paramagnetic" substances give information about the number of
Sita expects her future earnings to be worth Rs. 100. If she falls ill, her expected future earning will be Rs. 25. There is a belief that she may fall ill with probability of , -
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