Charge-Density-Wave Band Structure and Infrared and Visible Thermoreflectance of2H-TaSe2

We have measured the infrared and visible thermoreflectance of $2H$-Ta${\mathrm{Se}}_2$ in the charge-density-wave onset temperature range. New features that appear in the spectrum are compared with a model two-dimensional 3×3 charge-density-wave calculation. We stress connection between the infrared result and the multiplet of transitions inside the $d_{z^2}$ manifold.