Bulk AsxGe40-xSe60 (with x = 0; 10 and 20 at.%) glasses were repared using the melt-quench technique. Short range order (SRO) was examined by X-ray diffraction using CuðKaÞ radiation in the wave vector interval 0.28 < K < 6.5 (1/A).

For Ge40Se60 glass, the first sharp diffraction peak (FSDP) is located at K = 1(1/A) and shifted to higher K-values with increasing As content.Consequently, the coherence length has a maximum value for the binary glass.The SRO parameters have been obtained from the total distribution function, TðrÞ: The inter-atomic distances obtained from the first and second peak are, r1 = 2.37 (A) and r2 = 3.93 (A) in good agreement with previous works.The fundamental structural unit of the studied glasses is the Ge-Se4/2 tetrahedral.