分子動力学シミュレーションによるスメクタイト層間水の構造と物性の研究

低温科学

The relationship between molecular structure and the water-clay interaction of interlayer water in sodium type smectite were discussed using molecular dynamics (MD) simulations based on the free flexible force field model. Two distinct bands were found at 3365 and 3500 cm-1 in the stretching vibrational spectrum of interlayer water. The former was assigned to the O-H bond that was not bound to the clay surface, while the latter was attributed to O-H vibrations bound to the clay surface through hydrogen bonding. The hydrogen bond distance (H...O distance) between water and the clay surface (H water ... O clay = 0.22 nm) was larger than that between water molecules (H water...O water = 0.19 nm). Detailed comparisons of simulation results with IR spectroscopic observations indicated good agreement.