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Sulfur and Chlorine K-Edge X-ray Absorption Spectroscopic Studies of Photographic Materials
| Content Provider | Semantic Scholar |
|---|---|
| Author | Hedman, S. Britt Hodgson, Keith O. |
| Copyright Year | 1997 |
| Abstract | The sdfur and chlorine centers in spectral sensitizing dyes and surface modifing agents of importance to the photographic system were characterized by and Cl K-edge X-ray absorption spectroscopy (~S). The K-edge spectra of these compounds reveal sharp, characteristic absorption features that provide direct information about the local electronic and geometric environment of the absorber centers. In particdar, a sharp, intense pre-edge feature at 2470–2472 eV is s observed in the spectra of compounds containing exocyclic S (thione or thiol) that has no counterpart in the spectra of thiazole-containing (cyclic S) compounds. Singlecrystal polarized spectra reveal that the edge features of these compounds exhibit a strong orientational dependence, permitting the assignment of some of the observed features. The exocyclic S pre-edge feature was assigned to a S 1s ~ Z* transition, while the predominant spectral feature at 2473–2474 eV observed in all of the S Kedge spectra was found to be polarized along the H bond direction and assigned to a S 1s”~ O* transition. Dramatic changes in the sdfur-ligand spectral features are produced from complexation with Ag and Au atoms, which permits the distinction of covalent vs. ionic interactions with the metals encountered in photographic systems. Covalent metal-interaction with an exocyclic S-containing ligand resdted in the disappearance of the low-energy Z* pre-edge feature, while the intensity of the predominant O* feature in all compounds investigated was greatly enhanced upon complexation with Au and Ag metals. In contrast to the uncompleted ligands, this predominant feature was found to be most intense for polarizations along the S-metal direction and perpendicdar to the M bond, indicating a direct bonding interaction with the Au metal as seen, for example, in a bis(ethylenethiourea) Au(I) complex. The K-edge spectra of Cl centers, present as substituents on the ring system of the dye molecties, efibit a single predominant feature at approximately 2825 eV, which is ch~r~cteristic of the terminal GCl environment and is relatively insensitive to -structural changes in the dye systems more remote from the Cl centers. Single- |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.slac.stanford.edu/pubs/slacpubs/6250/slac-pub-6441.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Absorber Device Component Chlorine Covalent Interaction Diagnostic radiologic examination Direct bonding Dyes Gold Ionic License Ligands Metals PersonNameUse - assigned Pyschological Bonding Silver Sulfhydryl Compounds Supernumerary maxillary right third molar Thiazoles Thiones |
| Content Type | Text |
| Resource Type | Article |
