Neutron diffraction, chemistry, Microeconomics

Assignment Help:

chemistry assignmentsNeutron 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 setting

½ mv2 = 3/2 kT

And rearranging to get;

Mv = √3mkT

With appropriate numerical values, including 1.675 × 10-27 kg for the mass of a neutron, we obtain,

1.46 ×10-10 m = 146 pm

A 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. 


Related Discussions:- Neutron diffraction, chemistry

Advertising budget, Analyse the method by which a firm can allocate the giv...

Analyse the method by which a firm can allocate the given advertising budget between different media for advertisement?

Statistics, please can you explainn what "down 0.1 percentage point on the ...

please can you explainn what "down 0.1 percentage point on the quarter means"?

Indifference curve, explain the properties of indifference curve with the h...

explain the properties of indifference curve with the help of diagrams?

Just in time scheduling - jit, Just in Time Scheduling  - JIT JIT tec...

Just in Time Scheduling  - JIT JIT techniques are being widely adopted by operations managers in manufacturing companies in the West. JIT ideas have not only had a profound im

Economics Concepts, Suppose taht two people, Michell andJames each live alo...

Suppose taht two people, Michell andJames each live alone in an isolated region. They each have the same resources available, and they grow potatoes and raise chickens. If Michelle

Equibilium, Suppose Dlamini has R5 000 to spend on trousers and shirts. The...

Suppose Dlamini has R5 000 to spend on trousers and shirts. The price of trousers is R500 each and that of shirts is R312.50 each. 6.1 Use the information and calculate consumer eq

Tax incidence, if the inverse demand curve is p=120-Q and the marginal cost...

if the inverse demand curve is p=120-Q and the marginal cost constant at 10, how does the monopoly a specific tax of 10 per unif affect the monopoly optimum and welfare of consumer

Price elasticity of demand and supply, Price Elasticity of Demand is explai...

Price Elasticity of Demand is explained below: Price elasticity of demand/require is the percentage change in the quantity demanded with respect to the percentage change in the

Long period analysis, LONG PERIOD ANALYSIS: Long period refers to a ti...

LONG PERIOD ANALYSIS: Long period refers to a time when all the factors are variable. Earlier in the short period analysis, we had considered capital (K) to be fixed factor. H

MIF, What is the purpose of the IMF and why might the IMF be called the “le...

What is the purpose of the IMF and why might the IMF be called the “lender of last resort”? Discuss how three of the tools they use for establishing economic stability in a country

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd