Experimental Method of Rotating Crystal Method-Solid State Physics-Presentation, Slides of Solid State Physics

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Experimental Method

of “Rotating Crystal

Method”

Introduction

There are three

methods used for x-ray

diffraction. Rotating

crystal method is one

of them. As shown

below :

10

X-RAY DIFFRACTION METHODS

X-Ray Diffraction Methods

Laue Rotating Crystal Powder

Explanation…

13

ROTATING CRYSTAL METHOD

• In the rotating crystal method, a single crystal

is mounted with an axis normal to a

monochromatic x-ray beam. A cylindrical film

is placed around it and the crystal is rotated

about the chosen axis.

 As the crystal rotates, sets of lattice planes will at some point make the correct Bragg angle for the monochromatic incident beam, and at that point a diffracted beam will be formed.

Scattering by a Crystal

 - 2  a.S t= - t= - t= - t=4 t= - t= - t= 

• t=
  • t=

IN 3-D

18

By recording the diffraction patterns

(both angles and intensities) we can determine the shape and size of unit cell as well as arrangement of atoms inside the cell as shown in fib (b).

Film

19

Lattice constant of the crystal can be

determined by means of this method; for

a given wavelength if the angle at

which a reflection occurs is known ,

can be determined.

dhkl



2 2 2

a d h k l