Research on construction and optimization method of anthracite molecular model
In order to understand the molecular structure characteristics of coal,the testing methods such as elemental analy-sis,13 C-nuclear magnetic resonance(NMR),and Fourier transform infrared spectroscopy were used to construct a macromo-lecular model of anthracite.The results show that the aromatic carbon in the macromolecular model is dominated by C2 and C3 ring structures,and the molecular formula of the model is determined to be C193H138N2O7.After the structural and annealing optimization,the molecular model becomes more compact,with bond angles becoming more curved.After adding the periodic boundary conditions,the energy of the system decreases rapidly,which is mainly caused by the decrease of bond stretching en-ergy and van der Waals energy in non-bonding energy in the valence electron energy.The density of the optimal macromolecu-lar model of anthracite is 1.45 g/cm3 by density simulation.The research results can provide a reference for constructing the macromolecular models of coal.