Experimental and computer simulation study of the vibrational spectra of vermiculite

Infrared and Raman spectra of vermiculite clay have been recorded, and an assignment of the observed features in the spectra is proposed on the basis of molecular dynamics calculations. For this purpose, a force field yielding a structure and vibrational spectra in good agreement with the experimental data was developed with the help of ab initio calculations of models of vermiculite structural units. The calculated spectra of the periodic clay model are analysed in terms of symmetry adapted internal coordinates of the building units of the clay structure.