Theoretical investigation of thermodynamic properties of tetrabutylammonium bromide ionic clathrate hydrate

In the framework of the lattice dynamics method, the densities of the phonon states of tetrabutylammonium bromide ionic clathrate hydrate have been found. The dynamic stability of the hydrate is shown for a number of temperatures. Using the developed statistical-thermodynamic theory, the free energy curves have been constructed for a wide range of temperatures at different unit cell volumes and, based on the calculated data, the lines of thermal expansion of the hydrate have been constructed. (paper)