  The Canham--Helfrich free-energy density for a lipid bilayer involves the
mean and Gaussian curvatures of the midsurface of the bilayer. The splay and
saddle-splay moduli $\kappa$ and $\bar\kappa$ regulate the sensitivity of the
free-energy density to changes of these curvatures. Seguin and Fried derived
the Canham--Helfrich energy by taking into account the interactions between the
molecules comprising the bilayer, giving rise to integral representations for
the moduli in terms of the interaction potential. In the present work, two
potentials are chosen and the integrals are evaluated to yield expressions for
the moduli, which are found to depend on parameters associated with each
potential. These results are compared with values of the moduli found in the
current literature.
