Investigation of the local structure of nanosized CdS crystals stabilized with glutathione by the radial distribution function method

For stabilized nanoparticles of cadmium sulfide, a highly resolved radial distribution function was derived from the dispersion curve of synchrotron radiation (λ = 0.08824 A). The nanoparticle core has dimensions of 15 A–20 A and consists of Cd and S atoms in a 1:1 ratio. In the inner part of the nanoparticle, these atoms have a random tetrahedral coordination similar to that in crystalline CdS. Half of all core S atoms belong to the ligands and are coordinated by the surface Cd atoms. In contrast to the inner S atoms, these S atoms each binds two or three Cd atoms, forming a CdSCd bond angle of ≈100°, which is smaller than the tetrahedral angle. The Cd-S bond lengths are similar for both types of sulfur and vary within 2.52 A–2.53 A. The spatial arrangement of the Cd and S atoms beyond the first coordination sphere is significantly different from that of bulk CdS, which may be caused by perturbations induced by the surface S atoms.