UV spectral shift of benzene in sub- and supercritical water

UV absorption spectra of benzene have been measured over the wide range of temperature and pressure from the ambient state to the supercritical state (T = 400 °C and P = 40 MPa). The analysis of the spectral shift of benzene in water relative to that in the gas indicates that at T = 380 and 390 °C the local solvent density around benzene is likely to be depressed below the bulk density for densities near the critical density. It is found that π-hydrogen bond between benzene and water becomes evident with lowering temperature below T = 340 °C.