1. X-RAY DIFFRACTION
SPECTROSCOPY
PRESENTED BY
ENA ATHAIDE
Msc -1
INSTITUTE OF SCIENCE

2. Discovery of X- rays by Rontgen in
1895
X- rays: EMR ,short wavelength,
produced by electron transition of e-
inner orbital of atoms.
0.01 to 10 nm, 0.08- 0.2 nm most
useful.

4. X-ray generated by
X-ray tube (bombardment of metal target)
Radioisotopes
Secondary fluorescent sources

5. X-ray Tube

6. X-ray Diffraction
BRAGG’S Law for X-ray diffraction

7. 7
Bragg Equation
where, d is the spacing of the planes and n is the
order of diffraction.
• Bragg reflection can only occur for wavelength
The diffracted beams (reflections) from any set of
lattice planes can only occur at particular angles
predicted by the Bragg law.
 nd sin2
dn 2

8. Diffraction Condition
• The diffracted beams are found to occur when
the reflections from planes of atoms interfere
constructively.
• When path difference is equal to wavelength.

9. INSRTUMENTATION

10. X-RAY DIFFRACTION METHODS
X-Ray Diffraction Method
Laue Rotating Crystal Powder
Orientation
Single Crystal
Polychromatic Beam
Fixed Angle
Lattice constant
Single Crystal
Monochromatic Beam
Variable Angle
Lattice Parameters
Polycrystal (powdered)
Monochromatic Beam
Variable Angle

11. Rotating crystal method

12. 12
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.

13. Structure of DNA
This X-ray crystallography image of DNA shows a pair
of strong arcs along the vertical axis. Such pictures
gave Rosalind Franklin clues about the double helix
structure of DNA, but they do not reveal the
interactions between the crystallized protein and
other molecules.

15. Performing X-Ray Diffraction

16. Application of XRD
XRD is a nondestructive technique. Some of the uses of x-ray
diffraction are;
• Application in pharmaceuticals.
• Application in determination of protein
structure.

17. Advantages and disadvantages of
X-rays
Advantages;
• X-ray is the cheapest, the most convenient and widely used
method.
• X-rays are not absorbed very much by air, so the specimen
need not be in an evacuated chamber.
Disadvantage;
• They do not interact very strongly with lighter elements.

18. References
D.Skoog,F.Holler,S.Crouch,Instrumental analysis,
2008,Cengage Learning India pvt.Lt,pg:344 -359,367-370
K.Wilson,J.Walker,Practical biochemistry: principles
and Techniques,cambridge university press, 5th edition.
Clive whiston,1987,X-Ray methods: Analytical
chemistry by Open learning, British library,pg:1-29
Upadhya,Upadhya,nath,Biophysical
chemistry:Principles and techniques,2003,Himalaya
publishing house,3rd edition. pg:293-298

19. Park DJ, Choi Y, Heo S, Cho SY, Jin HJ, Bacterial
cellulose nanocrystals-embedded silk nanofibers,
2012 Jul;12(7):6139-44. PMID:
22966722,Pubmed,NCBI.
Zhang M, Song F, Wang XL,WangYZ,Development of
soy protein isolate/waterborne polyurethane blend
films with improved properties Colloids Surf B
Biointerfaces. 2012 Dec 1;100:16-21. Epub 2012
Jun 7, PMID: 22766279 [PubMed],NCBI.

20. ExperimentalMethodsinStructuralBiology
Proteinstructures.com/Experimental/Experimental
/protein-crystallography.html.