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

Abstract

For stabilized nanoparticles of CdS, a highly resolved radial distribution function was derived from the dispersion curve of synchrotron radiation (λ = 0.08824 Å). The nanoparticle core has dimensions of 15-20 Å 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 cryst. 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 2 or 3 Cd atoms, forming a Cd-S-Cd 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 2.52-2.53 Å. The spatial arrangement of the Cd and S atoms beyond the 1st coordination sphere is significantly different from that of bulk CdS, which may be caused by perturbations induced by the surface S atoms.