A Theoretical Investigation of the Effect of Intermolecular Correlations upon Properties of Simple Liquids from X-Ray Diffraction

Author: Piliavin, Michael Aron

Year: 1973

Degree: Dissertation (Ph.D.)

Advisor: Pings, Cornelius J.

Committee Member: Unknown, Unknown

Option: Engineering; Physics

Abstract

This work reports a theoretical study on the effect of including intermolecular correlations in x-ray scattering data from simple liquids.

An instantaneous configuration-dependent scattering factor is defined for a molecule in a liquid. Using statistical mechanics and physical principles, an expression is derived that corrects the usual scattering equations, for both coherent and incoherent radiation.

Computations, using the new result, were done on liquid helium and argon. Comparison of correlated scattering factors and isolated molecule scattering factors show significant deviations, especially for larger angles of scattering. Incorporating correlation effects into scattering data for these liquids, the resultant radial distribution function peak is depressed an average of 1% and the potential energy is lowered by 5%. Treatment of data in this manner leads to better agreement with theoretical predictions.

Files