Diffusion of intercalant atoms in stage-2 CsC24 and RbC24 graphite intercalation compounds

摘要

Quasi-elastic neutron scattering experiments on alkali-metalgraphite intercalation compounds are analyzed by treating the alkali-metal system as a viscous and dense two-dimensional liquid. The coherent scattering function and its full width at half maximum is analyzed by treating the potential between the intercalant atoms as a sum of two potentials. We have studied intercalant atoms diffusion in stage-2 CsC24 and RbC24 graphite intercalation compounds. We have shown that in the dynamic structure factor there is a competition between a single particle potential, due to the graphite bounding layers, which favours a registered for the alkali metal intercalant, and a pair potential between alkali atoms which prefers an unregistered phase. The explicit temperature dependence in the dynamic structure factor enters through the kinetic terms in the frequency moments. The other inputs like pair correlation function g(r) and the Fourier coefficients in the modulated potential have been taken from the experimental measurements at 3000k . We have taken them to be same at all values of the temperatures. This introduces appreciable error, especially at large temperatures. That is the reason why our calculated Δω show considerable error when compared with experimental measurements at high temperatures.