The optical properties of copper and gold as a function of temperature

The optical absorption spectra of copper and of gold have been measured polarimetrically as a function of temperature, while in ultra-high vacuum. The copper spectrum was obtained from 1·7-5·9 eV over the temperature range 77-920 °K and that of gold from 0·5-5·9 eV over the temperature range 295-770 °K. The main absorption peaks of both metals were found to vary with temperature and by comparison with calculations for the band structure of copper for various lattice parameters it was possible to identify peak positions with the following transitions: for copper, X5 -> X4prime at 3·97 eV, L2prime -> L1u at 4·78 eV and L11 -> EF(L2prime) at 5·32 eV, for gold L2prime -> L1u at 4·08 eV and X5 -> X4prime at 4·55 eV.