We report a revised analysis of extended x-ray-absorption fine-structure (EXAFS) spectra of the transition metal sulfides MnS, CoS, cubic (millerite) NiS, hexagonal NiS, heazelwoodite ${\mathrm{Ni}}_3$${\mathrm{S}}_2$, wurtzite ZnS, and GaS recorded at the S K edge. Near-neighbor distances are found to be within 0.02 Å of those derived from x-ray or neutron-diffraction data. We had previously reported an apparent breakdown of transferability of S-metal phase shifts for CoS and hexagonal NiS [D. R. Warburton et al., Phys. Rev. B 45, 12 043 (1992)] but this anomaly has now been resolved. This EXAFS analysis incorporates four enhancements: an improved procedure for background subtraction, the ability to fit data from crystals with a single scale factor as a multiplier for all distances, better treatment of vibrational effects, and incorporation of exchange and correlation terms according to the Hedin-Lundqvist prescription in the potentials for phase-shift calculation. Use of these procedures for Ni(110)c(2×2)S gives a nearest-neighbor S-Ni distance of 2.23±0.04 Å.

• Received 12 September 1994

DOI:https://doi.org/10.1103/PhysRevB.51.7905