Thermoreflectance of V, Nb, and paramagnetic Cr

Thermoreflectance measurements of V, Nb, and Cr films were performed near 80 and 340 K to investigate the electronic properties of these metals. The thermoreflectance spectra $\frac{\Delta R}{R}$ were Kramers-Kronig analyzed to determine the temperature dependence of the dielectric functions. The results were compared with previous derivative measurements of Mo and with static measurements of the optical reflectance of the bcc metals. Interpretation of the structures was guided by recent band calculations. It was shown that the observed features reflect the behavior of large volumes of the Brillouin zone rather than well-defined singularities.