... It can be applied to the studies of not only crystalline solids, but also to studies of various disordered, nanocrystalline, amorphous and liquid systems. In our laboratory we use EXAFS to study the local environment of isovalent and nonisovalent impurities in narrow-gap IV-VI semiconductors with a particular emphasis to off-center impurities which can induce the ferroelectric phase transition in these crystals. ... A.I. Lebedev, I.A. Sluchinskaya, V.N. Demin and I.H. Munro. ...