Interlayer-interaction for a lipid bilayer model

In order to elucidate the molecular basis of stability of lipid bilayer membranes, a system of two parallel monolayers consisting of oriented hydrocarbons with polar groups, which are oriented outwardly, is investigated. Relying upon the second-order perturbation theory of intermolecular forces between asymmetric molecules, a general expression for interlayer interaction energies is obtained for induced dipole-induced dipole, dipoleinduced dipole and dipole-dipole interactions. Using the polarizability tensor for a hydrocarbon unit C₂H₄, calculated after Smith & Mortensen (1960), and assuming 3 Debye unit for a dipole moment of a polar group, numerical estimations are performed.