POWD, an interactive program for powder diffraction data interpretation and indexing

An interactive program, POWD, written in Fortran77, for powder diffraction data interpretation and indexing is described. Various functions such as the least-squares refinement and the systematic absence test are also included in this versatile program. The modified de Wolff figure of merit [Wu (1988). J. Appl. Cryst. 21, 530-535] is introduced in the program to decrease the execution time and estimate the reliability of the indexing. Very high success rates for indexing and tolerance of the presence of limited impurity lines are demonstrated by testing the program on several groups of powder data.