CRYSTAL23

CRYSTAL is a general-purpose program for the study of crystalline solids, and the first which has been distributed publicly. The first version was released in 1988 and then seven next versions have followed: CRYSTAL92, CRYSTAL95, CRYSTAL98, CRYSTAL03, CRYSTAL06, CRYSTAL09, CRYSTAL14 and CRYSTAL17. The CRYSTAL program computes the electronic structure of periodic systems within Hartree Fock, density functional or various hybrid approximations (global and range-separated hybrids). The Bloch functions of the periodic systems are expanded as linear combinations of atom centred Gaussian functions. Powerful screening techniques are used to exploit real space locality. Restricted (Closed Shell) and Unrestricted (Spin-polarized) calculations can be performed with all-electron and valence-only basis sets with effective core pseudo-potentials. The program can automatically handle space symmetry (230 space groups, 80 two-sided plane groups, 99 rod groups, 45 point groups are available ). Point symmetries compatible with translation symmetry are provided for molecules. Helical symmetry is available (up to order 48). Input tools allow the generation of a slab (2D system), or a cluster (0D system), from a 3D crystalline structure, or the creation of a supercell with a defect, or single- and multi-wall nanotubes (1D system) from a single-layer slab model (2D system). The code may be used to perform consistent studies of the physical and chemical properties of molecules, polymers, nanotubes, surfaces and crystalline solids.