X-ray diffraction and Bragg's law
Crystal structure · Physics
Study notes
Step‑by‑step example: 1. A crystal has a lattice spacing d = 0.20 nm. 2. We use X‑rays with wavelength λ = 0.154 nm. 3. We want the first‑order (n = 1) diffraction angle θ. 4. Bragg’s law: nλ = 2d sinθ. 5. Plugging in the numbers: 1 × 0.154 = 2 × 0.20 × sinθ. 6. Solve for sinθ: sinθ = 0.154 / 0.40 = 0.385. 7. θ = arcsin(0.385) ≈ 22.6°. 8. So the first‑order diffraction peak appears at about 22.6 degrees.