Monte Carlo simulation of Lennardhyphen;Jones chains

摘要

Thermodynamical properties of lsquo;lsquo;infinitely stiffrsquo;rsquo; freely jointed Lennardhyphen;Jones chains are obtained through Monte Carlo simulation technique in the canonical (NVT) ensemble. A forcehyphen;bias sampling scheme is used in the simulation. The compressibility factor, energy, and constanthyphen;volume heat capacity of 8hyphen;, 16hyphen;, and 32hyphen;mer Lennardhyphen;Jones chains over wide ranges of densities and temperatures are obtained. It is known that the virial pressure of infinitely stiff freely jointed Lennardhyphen;Jones chains depends on twohyphen; and threehyphen;body correlations between segments. We determine, for the first time, these two contributions to the virial pressure of Lennardhyphen;Jones chains, and found that their relative magnitudes are comparable with each other. While the threehyphen;body term remains positive for all temperatures and densities examined, the twohyphen;body term adopts negative values at low temperatures and densities and positive values at high temperatures and densities. Our simulation results reveal the importance of threehyphen;body intrachain correlations that arise from chain connectivity and provide a quantitative basis for the assessment and development of theories for chain fluids.