The liquid structure of acetonitrile (AN) has been studied by the recently developed reverse Monte Carlo (RMC) simulation technique. This is the first attempt to apply the method to a heteroatomic molecular liquid. The basic simulation box contained 512 AN molecules. Each molecule was represented by three atomic sites, which were held together by "coordination constraints" allowing a realistic flexibility of the molecule. The generated configurations have been refined against experimental X-ray diffraction data. A Metropolis Monte Carlo simulation was also carried out and proved the reliability of the results of RMC. Partial pair correlation functions and angular and spatial distributions of the neighbors around a central molecule were calculated and analyzed in terms of predominant orientational configurations. A strong preference for antiparallel and a slight preference for parallel, head-to-tail, T- or L-shaped configurations were found, in qualitative accordance with previous results. These preferences however, decay rapidly after the first two to three neighbors. The average coordination number of the first shell resulted in five to six neighbors; moreover, different "orientational states" could be distinguished within the first coordination shell of molecules.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry