1. MENA3100, 27/1-09, OBK X-ray diffractionXRD Røntgendiffraksjon Single crystalPowder

2. Diffraction

4. Crystal Atomic arrangementLattice

7. X-ray diffraction Need X-rays Brehmsstrahlung = white radiation Characteristic X-rays Wavelenght CuK  1 = 1.54056 Å MoK  1 = 0.70930 Å CuK  1 = 1.54056 Å CuK  2 = 1.54433 Å CuK  = 1.5418 Å I(CuK  1 ) = 2·I(CuK  2 )

8. Need sample Single crystal Powder

9. Need experimental setup Diffractometer Bragg-Brentano geometry (Primary monochromator) (Secondary monochromator)

10. Want monochromatic radiation Brehmsstrahlung = white radiation Characteristic X-rays Monochromators: Many possibilities

11. Euclid, The Elements (300 B.C.) Proposition 21, Book III: The angles in the same segment of a circle are equal to another Johansson monochromator

12. Bragg-Brentano geometry The source S can be:

13. Need detector … Need some slits … S Sample Fixed slits: Smaler area at high angle  Smaller area at high angles Variable slits: Same area at all angles

15. The experiment Got some crystals Want a powder Gets lot of small crystals

17. Want powder Random orientation

18. The result The diffractogram Quartz (Don’t call it spectrum)

19. Why?

20. Identification PDF = JCPDS

21. Indexing

22. Lattice dimensions

24. Strain Particle size

25. Fluorescens

26. CuK  1 = 1.54056 Å CuK  2 = 1.54433 Å Primary and secondary monochromators

27. Rietveld refinement