Concept explainers
(a)
Show that the formula for low-energy electron diffraction (LEED), when electrons are incident perpendicular to a crystal surface, may be written as
(a)
Answer to Problem 14P
It is shown that the formula for low-energy electron diffraction (LEED), when electrons are incident perpendicular to a crystal surface, may be written as
Explanation of Solution
Write the expression for the diffraction condition for a crystal.
Here,
Write the expression for
Here,
Write the expression for
Here,
Use equation (III) in (II) to solve for
Use equation (IV) in (I) to solve for
Conclusion:
Therefore, it is shown that the formula for low-energy electron diffraction (LEED), when electrons are incident perpendicular to a crystal surface, may be written as
(b)
The atomic spacing in a crystal that has diffraction maxima at
(b)
Answer to Problem 14P
The atomic spacing in a crystal that has diffraction maxima at
Explanation of Solution
Use equation (V) to solve for the atomic spacing for the crystal.
Conclusion:
Substitute
Substitute
The atomic spacing in both cases,
Therefore, the atomic spacing in a crystal that has diffraction maxima at
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Chapter 5 Solutions
Modern Physics
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- Modern PhysicsPhysicsISBN:9781111794378Author:Raymond A. Serway, Clement J. Moses, Curt A. MoyerPublisher:Cengage Learning