Before Le Bail analysis “was the void”
Not exactly - 1981 - Pawley method -
- "Unit-cell refinement from powder diffraction scans", (G.S. Pawley J. Appl. Cryst. 14 (1981) 357-361)
- Unlike “classical” Le Bail fitting - Pawley fitting provides a correlation matrix
- Not easily implemented in existing Rietveld software
- When developed, was not matched up with the weak computer power due to each HKL being a parameter in the least squares matrix (1000 HKLs and 10 pattern/profile parameters = 1010 x 1010 least squares matrix)
- Available early implementations had a reputation of being unstable and difficult to control
- Only relatively recently that methods have improved to make the Pawley method a going concern and rival in usability to Le Bail method (all are restricted access and/or commercial(?))