12. A tetragonal lattice has fundamental lattice vectors a = ax, bay, and c = c2. The propagation vector for an incident

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12 A Tetragonal Lattice Has Fundamental Lattice Vectors A Ax Bay And C C2 The Propagation Vector For An Incident 1 (49.69 KiB) Viewed 26 times

12. A tetragonal lattice has fundamental lattice vectors a = ax, bay, and c = c2. The propagation vector for an incident beam of x rays is in the xy plane and makes the angle a with the x axis. (a) Take the wavelength to be λ and show that the (hk) elastic scattering peak occurs if h cos a + k sin a = λα Γ R2 + R2 a² 2 -- + 2]. (b) Show that no peaks with indices of the form (000) are produced. (c) Suppose λ = 1.54 Å, a = 4.73 Å, and c = 5.71 Å. Find the angle a the beam must make with the x axis to produce each of the following peaks: (100), (101), and (111). (d) Find the scattering angle for each of the peaks of part c.