CRYSTAL 98 1.0 February 26, 1999 V.R Saunder, R. Dovesi, C. Roetti, M. Causa, N.M. Harrison, R. Orlando, C. M. Zicovi

1. CRYSTAL 981.0February 26, 1999V.R Saunder, R. Dovesi, C. Roetti, M. Causa, N.M. Harrison, R. Orlando, C. M. Zicovish-Wilson Oleg Sychev

2. Crystal 98 2 Properties of interest&Methods Properties of interest Equilibrium structure Phonons Relaxation around defects Energy dispersion Density of states Spatial charge density Chemical bonding Magnetic interactions Dinamical simulations Phase boundaries

3. Crystal 98 3 Theory Stationary Shrodinger equation:

4. Crystal 98 4 TheoryHartree-Fock method

5. Crystal 98 5 TheoryDensity functional theory

6. Crystal 98 6 Installation Installation size is 173Mb on CD WWW Sites: http://www.chimifm.unito.it/teorica/crystal/crystal.html http://www.cse.clrc.ac.uk/cmg/CRYSTAL/

7. Crystal 98 7 Installation CRYSTAL98 use: Unix Linux systems(all versions) Windows NT

8. Crystal 98 8 Introduction The CRYSTAL package performs ab initio calculations of the ground state energy, elec-tronic wave function and properties of periodic systems. Hartree-Fock or Kohn-Sham Hamiltonians (that adopt an Exchange- Correlation potential following the postulates of Density-Functional theory) can be used. Systems periodic in 0 (molecules, 0D), 1(polymers, 1D), 2 (slabs, 2D), and 3 dimensions (crystals, 3D) are treated on an equal footing. In each case the fundamental approximation made is the expansion of the single particle wave functions ('Crystalline Orbital', CO) as a linear combination of Bloch functions (BF) defined in terms of local functions (hereafter indicated as �Atomic Orbitals�, AOs).

9. Crystal 98 9 Structure The local functions are, in turn, linear combinations of Gaussian type functions (GTF) whose exponents and coefficients are defined by input. Functions of s, p(in the order 2z2-x2-y2; xz; yz; x2-y2; xy) symmetry can be used. Also available are sp shells (s and p shells, sharing the same set of exponents).The use of sp shells can give rise to considerable savings in CPU time.

10. Crystal 98 10 Structure The program can automatically handle space symmetry: 230 space groups, 80 layer groups, 99 rod groups, 45 point groups are available (Appendix A). In the case of polymers it cannot treat helical structures (translation followed by a rotation around the periodic axis). However, when commensurate rotations are involved, a suitably large unit cell can be adopted. Point symmetries compatible with translation symmetry are provided for molecules. Input tools allow the generation of slabs (2D system) or clusters (0D system) from a 3D crystalline structure, the elastic distortion of the lattice, the creation of a supercell with a defect and a large variety of structure editing.

11. Crystal 98 11 Functionality The basic functionality of the code is outlined below. The single particle potential Restricted Hartree Fock Theory Unrestricted and Restricted Open Shell Hartree Fock Theory Density Functional Theory for Exchange and Correlation Effective Core Pseudopotentials

12. Crystal 98 12 Functionality Algorithms Parallel processing (replicated data) Traditional SCF Direct SCF

13. Crystal 98 13 Functionality Structural Editing Use of space, layer, rod and point group symmetry Removal, insertion deletion and substitution of atoms Displacement of atoms Rotation of groups of atoms Extraction of surface models from 3D crystal structure Cluster generation from 3D crystals Cluster of molecules from molecular crystals

14. Crystal 98 14 Functionality Properties Band structure Density of states Electronic charge density maps Electronic charge density on a 3D grid Mulliken population analysis Spherical harmonic atom and shell multipoles X-ray structure factors Electron momentum distributions Compton profiles Electrostatic potential, field and field gradients Spin polarised generalisation of properties Hyperfine electron-nuclear spin tensor A posteriori Density Functional correlation energy

15. Crystal 98 15 Wave function analysis and properties Total energy Hartree-Fock wave function Hartree-Fock wave-function+DF a posteriori correction for correlation DF SCF wave function Band structure Density of states Band projected DOSS AO projected DOSS All Electron Charge Density - Spin Density Density maps Mulliken population analysis Density analytical derivatives

16. Crystal 98 16 Wave function analysis and properties Atomic multipoles Electrostatic potential Electrostatic potential maps Point charge electrostatic potential maps Electric field Electric field gradient Structure factors Compton profiles Electron Momentum Density Fermi contact

19. Crystal 98 19 The functionality of the various programs and their links are as follows: integrals definition of geometry and BS calculation of symmetry information classification, selection, computation of one-and two-electron integrals

20. Crystal 98 20 Compilation Crystal98 is written in FORTRAN 77 and is therefore easily compiled on architectures for which executibles are not provided. You may also wish to compile the code to alter the dimensions of internal arrays or to select compilation and linkage options to increase the performance of the code.

21. Crystal 98 21 Testing the Installation It is very important that the installation of the code is checked by running the validation suite which is contained on the CD

22. Crystal 98 22 The parallel Implementation CRISTAL98 supports parallel execution on modestly parallel hardware on computers (nodes) linked by relatively low perfomance networks (eg: Ethenet).CPU and DISK resources are shared efficiently while the memory usage is replicated on each node. One node is chosen as the master.The master spawns the program onto other nodes (slaves) and operates dynamical load balancing of the task execution via a shared atomic counter. During integral generation a task is defined as the calculation of a block of integrals.Thus each node computes a number of integrals which are stored to its local disk.

23. Crystal 98 23 Basic problems of CRYSTAL98 Optimization basis for concrete physical tasks Value Energy Fermi is either overestimated(DFT method) or underestimated(HF-method) Time of calculation depends from computer sizes memory (as HDD size, so Extended memory size)

24. Crystal 98 24 CRYSTAL 981.0February 26, 1999V.R Saunder, R. Dovesi, C. Roetti, M. Causa, N.M. Harrison, R. Orlando, C. M. Zicovish-Wilson http://www.chimifm.unito.it/teorica/crystal/crystal.html http://www.cse.clrc.ac.uk/cmg/CRYSTAL/