Spheriodal multipolar expansions for intermolecular energy in crystal theory .: II. Lattice energy of the orthorhombic structure of actylene crystal

The spheroidal formalism for the interaction energy between two non-overlapping ellipsoidal charge distributions is applied to the determination of the lattice energy of the orthorhombic structure of the acetylene crystal. The molecules are assimilated to quadrupolar prolate ellipsoids and the pair potential is assumed to be a sum of two terms: a Kihara corepotential extended to prolate ellipsoids and the spheroidal quadrupolar interaction. The value so obtained for the lattice energy is ?25.01 kJ mole^? while an evaluation of the corresponding observed value is ?23.81 kJmole^?.