Spherical-harmonic reconstruction of liquids diffraction data

✍ Scribed by A.K. Soper

• Book ID: 103941035
• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 528 KB
• Volume: 213-214
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(95)00366-h

✦ Synopsis

Diffraction data from liquids and amorphous materials are normally analysed in terms of the pair-distribution function, 9(r). This function represents the likely density of neighbouring atoms, given an atom at the origin. For a long time the lack of long-range order in a liquid has eluded attempts to establish a three-dimensional structure of a liquid consistent with the diffraction data in the way that is achieved in crystallography. The spherical-harmonic expansion is introduced as a way around this difficulty. Essentially the correlation function of interest is expanded as series of spherical-harmonic functions, the coefficients of which, labelled by integers, need to be determined to be compatible with the diffraction data. The power of the method arises from the fact that awkward integrals over angular coordinates are replaced by simple sums over the coefficients and this results in considerable economy in representing the correlation function of interest. Recent applications to the structure of water and liquid dimethyl sulfoxide are used to test and illustrate the method.