First principles computation of lattice energies of organic solids: The benzene crystal

We provide a first-principles methodology to obtain converged results for the lattice energy of crystals of small, neutral organic molecules. In particular, we determine the lattice energy of crystalline benzene using an additive system based on the individual interaction energies of benzene dimers, Enthalpy corrections are estimated so that the lattice energy can be directly compared to the experimentally determined sublimation energy. Our best estimate of the sublimation energy is 49.4 kJmol(-1), just over the typical experimentally reported values of 43-47 kJmol(-1). Our results underscore the necessity of using highly correlated electronic structure methods to determine thermodynamic properties within chemical accuracy. The first coordination sphere contributes about 90% of the total lattice energy, and the second coordination sphere contributes the remaining 10%. Three-body interactions are determined to be negligible.