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Crystallography lv.

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Presentation on theme: "Crystallography lv."— Presentation transcript:

1 crystallography lv

2 Useful concept for crystallography & diffraction
Lattice planes Useful concept for crystallography & diffraction Think of sets of planes in lattice - each plane in set parallel to all others in set. All planes in set equidistant from one another Infinite number of sets of planes in lattice d d - interplanar spacing

3 Keep track of sets of planes by
giving them names - Miller indices (hkl) Lattice planes

4 Miller indices (hkl) Choose cell, cell origin, cell axes: origin b a

5 Miller indices (hkl) Choose cell, cell origin, cell axes Draw set of planes of interest: origin b a

6 Miller indices (hkl) Choose cell, cell origin, cell axes Draw set of planes of interest Choose plane nearest origin: origin b a

7 Miller indices (hkl) Choose cell, cell origin, cell axes Draw set of planes of interest Choose plane nearest origin Find intercepts on cell axes: 1,1,∞ origin b 1 a 1

8 Miller indices (hkl) Choose cell, cell origin, cell axes Draw set of planes of interest Choose plane nearest origin Find intercepts on cell axes 1,1,∞ Invert these to get (hkl) (110) origin b 1 a 1

9 Lattice planes Exercises

10 Lattice planes Exercises

11 Lattice planes Exercises

12 Lattice planes Exercises

13 Lattice planes Exercises

14 Lattice planes Exercises

15 Lattice planes Exercises

16 Lattice planes Exercises

17 Lattice planes Exercises

18 Lattice planes Exercises

19 Lattice planes Exercises

20 Lattice planes Exercises

21 Lattice planes Exercises

22 Lattice planes Exercises

23 Lattice planes Exercises

24 Lattice planes Two things characterize a set of lattice planes: interplanar spacing (d) orientation (defined by normal)

25 For hexagonal lattices - sometimes see 4-index
Strange indices For hexagonal lattices - sometimes see 4-index notation for planes (hkil) where i = - h - k a3 a1 a2 (110) (1120)

26 2 intersecting lattice planes form a zone
Zones 2 intersecting lattice planes form a zone zone axis zone axis zone axis [uvw] is ui + vj + wk i j k h1 k1 l1 h2 k2 l2 plane (hkl) belongs to zone [uvw] if hu + kv + lw = 0 if (h1 k1 l1) and (h2 k2 l2 ) in same zone, then (h1+h2 k1+k2 l1+l2 ) also in same zone.

27 zone axis [uvw] is ui + vj + wk
Zones Example: zone axis for (111) & (100) - [011] zone axis [uvw] is ui + vj + wk i j k h1 k1 l1 h2 k2 l2 i j k (100) (111) [011] (011) in same zone? hu + kv + lw = 0 0·0 + 1·1 - 1·1 = 0 if (h1 k1 l1) and (h2 k2 l2 ) in same zone, then (h1+h2 k1+k2 l1+l2 ) also in same zone.

28 Reciprocal lattice Real space lattice

29 Real space lattice - basis vectors
Reciprocal lattice Real space lattice - basis vectors a a

30 Real space lattice - choose set of planes
Reciprocal lattice Real space lattice - choose set of planes (100) planes n100

31 Real space lattice - interplanar spacing d
Reciprocal lattice Real space lattice - interplanar spacing d (100) planes d100 1/d100 n100

32 Real space lattice ––> the (100) reciprocal lattice pt
planes d100 n100 (100)

33 Reciprocal lattice The (010) recip lattice pt n010 (010) planes d010
(100)

34 The (020) reciprocal lattice point
planes d020 (010) (020) (100)

35 More reciprocal lattice points
(010) (020) (100)

36 The (110) reciprocal lattice point
planes n110 d110 (010) (020) (100) (110)

37 Still more reciprocal lattice points
(010) (020) (100) the reciprocal lattice (230)

38 Reciprocal lattice Reciprocal lattice notation

39 Reciprocal lattice Reciprocal lattice for hexagonal real space lattice

40 Reciprocal lattice Reciprocal lattice for hexagonal real space lattice

41 Reciprocal lattice Reciprocal lattice for hexagonal real space lattice

42 Reciprocal lattice Reciprocal lattice for hexagonal real space lattice

43 Reciprocal lattice


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