Angularly Resolved Density Distributions–A Starting Point for Analysis of Liquid Structure

Abstract

We propose that the angular unfolding of atomic density distributions exposes some main features of liquid structure. Examples are the mass and the angular location of major maxima. Such structural features constitute a useful starting point for the analysis of liquid structure. To demonstrate this we have analyzed a molecular dynamics trajectory of an equimolar water-acetonitrile mixture. A new method to characterize the extrema of density distributions is used for the analysis. Using this method we draw some conclusions about different types of hydrogen bonds, their lifetimes, and their associated transition probabilities. We also draw some conclusions about recurrent molecular pair configurations.

Key Words:

• Liquid structure
• spatial distribution function
• molecular mixture
• molecular dynamics simulation
• water
• acetonitrile