Simultaneous peak-shift correction in the least-squares determination of unit-cell parameters of a sample with standard reference material

A straightforward method for the systematic peak-shift correction using the standard reference material is proposed for the least-squares determination of unit-cell parameters. It requires no pre-determined angle-calibration curve, and the peak-shift correction can be applied simultaneously during the least squares. The procedure, programmed with Fortran 77 statements, has been tested with powder diffractometer data of an α-SiO₂ + Si mixture. Advantages of the procedure are: (i) all reflection data from both sample and standard reference material contribute to determining the angle-dependent calibration curve, and (ii) one reflection from the standard reference material suffices for the correction of systematic errors.