Comparison of structural theories for graphite intercalation compounds

Alkali liquids intercalated in graphite are subject to a strong periodic host potential. We compare here two theories for the modulation induced in the alkali density that result in different approximations for higher-order correlations, with computer simulations and experimental data. We show these two theoriesone based on a cumulant expansion, the other on an angular truncation of the Lovet-Mou-Buff equationagree analytically in the limit of weak host potential and are numerically similar at high temperatures for a realistic potential.