Raman spectral changes of CO2 induced by the absorption were evaluated for the Fermi dyad continuously up to 15 MPa of equilibrium CO2 pressure. Little pressure dependence was observed for both the band positions and the bandwidth of the absorbed CO2, compared to those for neat supercritical CO2. Furthermore, the band positions lay at much lower values than those for neat CO2. The bandwidth broadening was observed for the absorbed CO2 even in the lower pressure region. The absorption state of CO2 is discussed from the viewpoints of structural fluctuations and interaction forces induced by the surrounding ionic liquid. (C) 2017 Elsevier B.V. All rights reserved.