Model of short-range order in liquid bicyclohexyl from X-ray diffraction studies

The structure of liquid bicyclohexyl, C6H11-C6H11 at 293 K was investigated using the X-ray diffraction method. Monochromatic radiation CuKalpha enabled one to determine the scattered radiation intensity between S-0=4 pi sin theta (0)/lambda =0.417 Angstrom (-1) and S-max=7.06 Angstrom (-1). The angular distribution of X-ray radiation scattered was measured, and electron-density radial-distribution function (EDRDF) was numerically found using Fourier analysis. A good agreement between the theoretical and experimental functions was obtained on assuming the statistically most probable model of this molecule. The structural data obtainable by X-ray analysis for liquid bicyclohexyl were discussed. The mean distances between the neighbouring molecules were found. The maxima in the EDRDF were at : (r) over bar (1) = 4.68, (r) over bar (2) = 5.57, (r) over bar (3) = 6.62, (r) over bar (4) = 8.05 Angstrom. Computer techniques were used to minimize the effects of experimental errors, uncertainties in the scattering factors, and termination errors. X-ray structural analysis was applied to determine the packing coefficient of bicyclohexyl molecules. A simple model of short-range arrangement of the molecules in liquid bicyclohexyl was proposed. (C) 2000 Elsevier Science B.V. All rights reserved.