ROLE OF PT2+ AND PT4+ IMPURITY IONS IN PHOTOCHEMISTRY OF SINGLE-CRYSTAL SILVER-CHLORIDE

Both divalent and tetravalent platinum ions are substitutionally incorporated into silver chloride during the melt growth of single crystals. Pt2+ is believed to occupy sites of octahedral or tetragonal symmetry which are formulated as {PtCl6}4- and {(PtCl 6)4-·Agvac+}, respectively. The former complex functions as an electron trap, whereas the charge-compensated center has a significant capture cross section for holes. The predominant products of these reactions, (PtCl6)5- and {(PtCl 6)3-·Agvac+}, where n = 1 to 3, have been identified by EPR spectroscopy. Pt4+ ions are fully charge compensated in AgCl, and the resultant complex, {(PtCl6) 2-·3Agvac+}, is a deep electron trap. The most stable photoproduct from both AgCl|Pt2+| and AgCl|Pt 4+| was ((PtCl6)3-·2Ag vac+). The lifetime at room temperature and the trap depth for this complex have been determined. © 1978 American Institute of Physics.