The ultraviolet absorption spectrum of hot carbon dioxide

The vacuum ultraviolet absorption spectrum of CO2 shifts significantly to longer wavelengths with increasing temperature. We have measured this temperature dependence and present absorption cross sections for 230 to 355 nm at temperatures from 1523 to 2273 K. At 2273 K this red shift extends the absorption above 300 nm and well into the blue end of the solar spectrum. In CO2 the thermal shift is enhanced because of the relative position and shapes of the excited and ground state potential curves.