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

Demand function is homogeneous of degree zero, Demand Function is Homogeneo...

Demand Function is Homogeneous of Degree Zero: Mathematical Presentation  we will show that demand function is homogeneous of degree zero in prices and money income. In o

Mba, Is Indian companies running a risk by not giving attention to cost cut...

Is Indian companies running a risk by not giving attention to cost cutting

Name the actors in the basic neoclassical model of economics, Name the two ...

Name the two actors in the basic neoclassical (or traditional microeconomic) model of economics, and identify the assumptions the model makes of these two actors. Firms and hou

Illustrate the term less developed and developed countries, How might one m...

How might one measure differences in living standards between less developed and developed countries?  This is a very wide question where any clear and relevant calculate shoul

Elasticity, You estimate that the price elasticity of demand for one-acre p...

You estimate that the price elasticity of demand for one-acre plots in Lusaka is -1.5 and that income elasticity of demand is 5. Land owners intend to increase the price of a one-a

Describe primary interests and theory of supply and demand, Part 1 - Sele...

Part 1 - Select a construction-based business of your choice and explain stakeholder theory to illustrate the primary interests of the stakeholder groups and identify any areas o

Input substitution when the input price change, Input Substitution When the...

Input Substitution When the Input Price Change  Isoquants and Isocosts and Production Function The minimum cost combination can be written as: - Minimum cost

Contribution of foreign trade to economic development, Contribution of Fore...

Contribution of Foreign Trade to Economic Development: Foreign trade contributes to economic development in a number of ways.  •  It provides flow of technology which al

What do you meant by informal economy, Q. What do you meant by Informal Eco...

Q. What do you meant by Informal Economy? Informal Economy:Informal sector of the economy represents the production of services and goods for the own-use of the producers or fo

Use arc elasticity to find the price elasticity of demand, Elasticity- a...

Elasticity- a) The price of good X goes up by 2.75%, the quantity demanded of good Y goes from 10,500 units to 25,000.  What is the Exy?  What does that number mean?  What is th

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