Pressure dependence of acetophenone N,N,N′,N′-tetramethylbenzidine exciplex in supercritical carbon dioxide

The pressure dependence of the formation and decay processes of exciplex between two neutral species acetophenone (AP) and N,N,N′,N′-tetramethylbenzidine (TMB) in supercritical carbon dioxide was investigated by a transient absorption technique at 40 °C and at pressures from 9.0 to 14.7 MPa. The exciplex formation rate constant could be described by the Stokes–Einstein/Debye (SE/D) equation. The trend of the exciplex decay rate constant showed local density augmentation around the exciplex in the low-pressure region.