K. Ueda, T. Ishikawa, H. Miyamoto, D. Hayakawa
Yokohama National University, Japan
pp. 95 - 98
Keywords: ab initio molecular dyanmics, crystal structure, cellulose
The structure and the interactions existing in the crystal of cellulose IIII was evaluated by using the computational chemical approach. Cellulose is one of the most abundant renewable resources and the application of it to use as a future energy and materials has been progressing. In this study, we performed the optimization and ab initio molecular dynamics simulation of cellulose IIII to investigate the detail information of it. We previously performed the geometry optimization with variable-cell relaxation using the Quantum ESPRESSO program and showed that it is in good agreement with the experimentally obtained crystal structure. However, the cell parameters were slightly smaller than the experimental one which was observed at an ambient temperature. The smaller cell parameter can be considered as an effect of the thermal expansion. That is, the optimized structure with density functional theory corresponds to that at 0K. Therefore, in this work, we performed ab initio molecular dynanics simulation at the temperature from 0K to 500K and investigated the temperature effect of the cell parameters. The results showed that the thermal expansion, especially in the “a” axis direction, was observed during the increment of the temperature.