Study on refractive index, EOS and polarizability of atomic, molecular and mixted gases at high pressures up to 60 MPa

The refractive index of initially transparent gases at high pressures is very important for shock velocity measurements in shock compression experiment since the measured shock velocity has to be modified by the refractivity of the initial smaple. In this work, bu using optical frequency domain interferometer (OFDI), we measured the refractive index of atomic (He, Ne, Ar, Kr, Xe), molecular (H2, D2, O2, N2, CO, CH4) and mixed gases (H2-D2, H2+Ar, D2+He, He-Ar, He-Xe) up to 60 MPa. The EOS of part of above gases were measured experimentally, while others were calculated. The polarizability of different gases were derived from their refractive index and density according to Lorentz-Lorenz formula. The mixing rule below 60 MPa were verified by the experimental results of mixed gases investigated in this work.