Optical spectroscopy of bulk metals

A brief tutorial discussion is presented which emphasises the capabilities of optical spectroscopy as a tool for investigating the electronic structure of the transition metals. Two transition metals, Nb and Ta, are discussed in detail as examples to show what kind of information results from optical studies. The low-energy spectral range is emphasised. Thermoreflectance studies of bulk Nb and Ta are discussed, and it is demonstrated that they reveal structures which static absorptivity/reflectivity measurements fail to resolve. Static and thermoreflectance measurements with the hydrides of Ta and Nb are discussed, and it is shown that these results are valuable in understanding both the hydrogen-metal interaction and the metal states themselves. (author)