7785-23-1Relevant academic research and scientific papers
Photoelectron spectroscopy of AgCl, AgBr, and AgI vapors
Berkowitz, J.,Batson, C. H.,Goodman, G. L.
, p. 5829 - 5837 (1980)
He I photoelectron spectra of AgCl, AgBr and AgI vapors have been obtained which differ significantly from earlier work.In each instance, the characteristic features of the diatomic molecule are prominent.The spectral features separate into a valence region, predominantly halogen p-like, and a deeper region, predominantly of Ag 4d character.The latter is split by spin-orbit and ligand field interactions, which are parametrized from the experimental data.Relativistic calculations of the Xα-DVM-SCC type have been performed for these species.At the transition statelevel, they agree very well with the experimental peak positions.Nonrelativistic calculations of this type have been performed for CuCl and cyclic Cu3Cl3.Unlike the AgX species, the CuCl and Cu3Cl3 exhibit strong mixing of metal d and halogen p orbitals for the uppermost occupied orbital, and other Cu 3d-like orbitals above the Cl 3p-like orbitals.It is suggested that the occurrence of Cu 3d orbitals in the valence region may play a role in the anomalous diamagnetic signal and large conductivity changes of CuCl condensed from the vapor.
Growth Mechanisms of Silver Halide Clusters from the Molecule to the Colloidal Particle
Hayes, David,Schmidt, Klaus H.,Meisel, Dan
, p. 6100 - 6109 (2007/10/02)
Studies of growing silver halide clusters, from the molecular level to colloidal-size particles, have been undertaken and correlations between particle size and physical properties have been investigated.The production of halide ions by dissociative electron attachement following pulse radiolysis of methylene halide solutions was utilized to instantaneously produce homogeneous, supersaturated solutions of halide and silver ions.The grows of silver halide particles in these solutions has been examined by conductance, absorption spectroscopy, and light scattering measurements.Conductivity measurements show that the initial reaction between the ions occurs at a diffusion-controlled rate and allow determination of the stability constants of molecular silver halide species.In solutions containing excess silver ions, particle growth of silver iodide and bromide occurs via a diffusion-controlled aggregation mechanism during the first seconds.The grows rate is reduced significantly, due to electrostatic repulsion between particles, when the concentation of halide ions is almost equal to or greater than the stoichiometric concentration of silver ions.The absorbance of silver iodide suspensions produced in this manner has also been measured.The initial absorbance, due to AgI molecules, occurs at wavelengths of 280 nm and below.The lowest energy excitation band appears ca. 50 μs after initiation of the reaction.This band initially peaks at around 320 nm and shifts toward 425 nm (the wavelength of excitation absorption in bulk silver iodide).The surface potential at the interface evolves at about the same rate as the bulk properties of the material.For the mostly dissociated AgCl molecules growth by addition of ions to a small number of particles of critical size was observed.
