Low-temperature donor-acceptor recombination in silver halides

The time and wavelength evolution of the optical emission from AgCl and AgBr at low temperature (∼4 K) has been investigated. These data characterize the emission from AgCl (${\lambda }_{\max }$=500 nm) as partially due to donor-acceptor recombination and from AgBr (${\lambda }_{\max }$=580 nm) as wholly due to donor-acceptor recombination. These conclusions are supported by optically detected magnetic resonance data and other spectroscopic information, which suggest that the donors are interstitial silver ions or substitutional divalent-cation impurities and that the acceptor in AgCl is a self-trapped hole.