LAUSR

We have measured the reflectance of rhenium in the visible region to pressures up to 100 GPa in a diamond anvil cell (DAC). By photographing the reflecting surface, we visually show that there are challenges to obtaining accurate values in a DAC for several reasons and propose some useful procedures. We also show that knowledge of the reflectance of rhenium can overcome the problem of absorption of light by diamonds when studying the reflectance of materials at high pressure in a DAC. 1. Current address: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. 2. Current address: Dept. of Chemistry and Biochemistry, Florida International University, 11200 SW 8t St, Miami, Fl 33199. *Equal contributions. **Corresponding author. Email: [email protected]