Optical absorption spectra of liquid As2S3and As2Se3over a wide temperature range

The authors have measured the optical absorption coefficient of liquid As 2 S 3 and As 2 Se 3 up to 900 degrees C in a wide absorption range up to about 3*10 5 cm -1 . They have developed an optical cell of their own design with a sample thickness of about 2000 AA. The optical gap obtained from the spectra decreases rapidly with increasing temperature, eventually becoming zero at about 950 degrees C for liquid As 2 Se 3 , where the semiconductor-to-metal transition starts to occur.