This document discusses x-ray diffraction methods. It begins with a brief history of x-rays being discovered in 1895 by Wilhelm Roentgen in Germany. It then describes how x-rays are produced when electrons strike a metal target, and how x-ray diffraction occurs via constructive and destructive interference of x-rays hitting a crystalline sample. Bragg's law from 1913 relates the angles and wavelengths of diffracted x-rays to the sample's structure. Finally, it lists several applications of x-ray diffraction such as determining atomic structures of crystals, proteins, DNA, and its use in identifying materials in fields like pharmaceuticals.

1. X-Ray Diffraction Methods
Ms. Isha Rani
(Assistant Professor)
M.M. College of Pharmacy,
Maharishi Markandeshwar (Deemed to be University)
Mullana, Ambala- Haryana, India

2. Contents
1) Introduction
2) History of X-rays
3) Production of X- Rays
4) Diffraction
Constructive Diffraction
Destructive Diffraction
5) Bragg’s Law
6) Application

3. Introduction
X Ray Crystallography: It is a experimental technique help us to determine the
atomic and molecular structure of a crystal.

4. History of X-rays
X-rays were discovered in 1895 by Wilhelm Roentgen in
Germany when he was working with cathode-ray tube
in his laboratory.
He got Noble prize in 1901.
First human’s hand X ray of
Roentgen's wife

5. Properties of X rays
 X rays travel in straight lines.
 X rays are invisible.
 X rays have very short wavelength ranging from 0.01-10 nm.
 X rays are diverging rays i.e. they can not be focused on a single point.
 X rays are not affected by electromagnetic radiations.
 They can produce photoelectric effect.
 X rays have high penetrating power.

6. Production of X rays
X rays are produced when rapidly moving electrons strike with
metallic object (tungsten). The incoming electrons release X rays.
(Reverse of photoelectric effect)

7. X-Ray Diffraction
X ray diffraction based on constructive interference of mono
chromatic x rays and crystalline sample.
The interaction of incident ray and sample produces constructive
interference (a diffracted ray) which satisfy Bragg’s law.

8. Constructive interferences
Constructive interferences is when two waves superimpose and the
resulting wave has a higher amplitude than previous.
PD=nλ (n=0,1,2,3)
.

9. Destructive interferences
Destructive interferences is when two waves superimpose and cancel
each other out, resulting to lower amplitude.
PD=nλ (n=λ/2, 3λ/2, 5λ/2

10. Bragg’s Law
In 1913 W.H. Bragg and his son W.L. Bragg developed a relationship
called Bragg’s law to explain x ray diffraction.
nλ=2d sin θ

11. Applications
• Determine size of atoms, length and different type of bonds, atomic
arrangement and structure of crystal.
• Used to identify various biological materials, vitamins, drugs, thin film
materials and multi layered materials.
• Useful in pharmaceutical sector due to non destructive nature.
• This technique is usefull to determine proteins structure.
• Double helix structure of DNA also identify by this technique.

12. Thank you!!!