Sound velocity and refractive index of pure N2 fluid and of equimolar N2 –CO2 fluid mixture up to 15 GPa

S. Ninet (1) , Frédéric Datchi (1) , G. Weck (2) , A. Dewaele (2) , P. Loubeyre (2) , V. Giordano (3)

1 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
2 DAM/DIF - DAM Île-de-France
3 ENERGIE - (nano)Matériaux pour l'énergie

The sound velocity and refractive index of pure N₂ and of the equimolar N₂–CO₂ mixture are measured up to 15 GPa and 700 K in a resistive heating diamond anvil cell. The refractive index vs pressure is obtained by an interferometric method. The adiabatic sound velocity is then determined from the measurement of the Brillouin frequency shift in the backscattering geometry and the refractive index data. No phase separation of the N₂–CO₂ fluid mixture is observed. The fluid mixture properties are discussed in terms of ideal mixing.

Mots clés: Thermodynamic states and processes; Light scattering; Sound velocity measurement; Equations of fluid dynamics; Acoustical properties; Diamond anvil cells; Brillouin spectroscopy; Optical properties

Domaines: Matière Condensée [cond-mat]

S. Ninet, Frédéric Datchi, G. Weck, A. Dewaele, P. Loubeyre, et al.. Sound velocity and refractive index of pure N2 fluid and of equimolar N2 –CO2 fluid mixture up to 15 GPa. Journal of Chemical Physics, 2020, 153 (11), pp.114503. ⟨10.1063/5.0021678⟩. ⟨hal-02954826⟩