Full Betterprof ⏰ ⭐

This is written as a for a user who already has diffraction data (X-ray or neutron) and a .pcr file. Piece for FullProf: From .dat to Refined Structure 1. Core Philosophy FullProf refines a crystal structure by minimizing the difference between an observed powder pattern and a calculated one. Input: .pcr (plain text control file) + .dat (observed pattern) Output: .out (refinement log), .sum (final calculated pattern), .brg (Bragg positions) 2. Essential File Structure ( .pcr ) A .pcr file is divided into 12–14 lines of header (instrument, pattern, background) plus profile and structural blocks. Minimal working block structure: ! Title line ! Comments ! Mode: (e.g., RM - Rietveld with constant wavelength) ! Instrument parameters (zero shift, wavelength) ! Pattern range (2theta min, max, step) ! Background coefficients (polynomial or interpolation) ! Phase number & name ! Space group (e.g., F m -3 m) ! Lattice parameters (a, b, c, alpha, beta, gamma) ! Atomic positions (x, y, z, occ, Biso) ! Profile parameters (U, V, W, asymmetry, etc.) ! End of phase ! Refinement flags (0 = fixed, 1 = refined) 3. Typical Workflow (Command Line) # 1. Run refinement fullprof < myfile.pcr 2. View results (text) less myfile.out 3. Generate plots (WinPLOTR) winplotr myfile.pcr 4. Convert .sum to .xy for external plotting gfourier myfile 4. Key Refinement Steps (for beginners) | Step | Action | |------|--------| | 1 | Start with correct zero shift, scale, and background. | | 2 | Refine lattice parameters only. | | 2 | Add profile parameters (U, V, W – Caglioti). | | 3 | Refine atomic coordinates (if needed). | | 4 | Refine thermal factors (Biso). | | 5 | Refine occupancy (only for mixed sites). | | 6 | Check Rwp , Rexp , GoF (chi²). |