Determination of the structure of liquids containing free radical molecules: Inter-molecular correlations in liquid chlorine dioxide

摘要

X-ray diffraction spectra of liquid ClO_2 at 204, 223, 248 and 273 K were measured at the BL04B2 beamline in the SPring-8 synchrotron radiation facility. The obtained structure factors are well reproduced by reverse Monte Carlo (RMC) structural modelling. With increasing temperature, the first peak located at around Q = 1.8A° -1 slightly shifts to higher Q and the tail at the lower-Q side intensifies. In the pair distribution function, g(r), the intensity of the peak at around 3.2A° that corresponds to the nearest-neighbour distance decreases with increasing temperature. The analysis of the RMC configurations shows that strong directional O-O interaction exists in liquid ClO_2 and the instantaneous inter-molecular orientation depends on this interaction.