The optical absorption of thin films of silver monofluoride has been investigated in the visible and ultraviolet region of the spectrum at room and low temperatures. Exciton peaks have been observed at 4.63 and 6.34 eV for samples at 4.8 °K. The first exciton peak is considerably lower in energy than might be expected on the basis of the trend set by the other silver halides. This unusually low energy has led us to speculate that the band structure of AgF may be quite different from those of the other silver halides.

• Received 9 December 1970

DOI:https://doi.org/10.1103/PhysRevB.3.2604