In the News..11-12-2007 Amsterdam Density Functional Package ADF 2007 software package performs electronic structure calculations using Density Functional Theory (DFT). New Features
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ADF software for chemistsThe ADF package consists of:
The underlying theory of the ADF package is density functional theory (DFT). The success of DFTThe Kohn-Sham approach to DFT implies a one-electron picture of a many-electron system but yields in principle the exact electron density, total energy, and any other property. DFT has dominated quantum chemistry applications since the early 1990s, as it gives superior accuracy to Hartree-Fock theory and semi-empirical approaches, and is well suited for molecules containing metal atoms. In contrast to conventional ab initio methods (MP2, CI, CC), it enables accurate treatment of systems with several hundreds of atoms (or several thousands with QM/MM). 
Charge distribution on acetone The molecular ADF program can be applied to gas phase molecules, solvated molecules, and molecules in protein environments providing a comprehensive solution across the whole of the of the periodic table. Main Features of ADF & BAND:Structure and Reactivity
(The SN2 substitution at carbon & silicon. With ADF one can understand why it proceeds via qualitatively different potential energy surfaces.) ADF supports geometry optimizations in delocalized, Cartesian, and internal coordinates. An initial Hessian estimate speeds up the optimizations. Combined, initially unsatisfied, and other constraints can be imposed. Transition state searches (via Nudged Elastic Band and Eigenvector Following methods), intrinsic reaction coordinates, and linear transit calculations are available to further analyze the energy path from reactants, via the transition state, to the final products. The new analytic second derivatives implementation rapidly yields Hessians for GGA functionals, which are helpful in finding and characterizing the transition states:
Model HamiltoniansThe relativistic methods (ZORA and spin-orbit coupling) and basis sets in ADF enable treatment of molecules with very heavy elements. The ADF approach removes the need for pseudopotential and effective core potential (ECP) approximations, even for lanthanides and actinides. Users recommend ADF for its ability to provide the same stability for complex open-shell transition metal compounds as for simpler systems containing only light atoms.
Spectroscopic properties
The IR spectrum of ethene visualised with ADFspectra An important strength of ADF is the variety of accessible properties and the accuracy with which they can be obtained, including standard properties like electron densities, multipole moments and electrostatic potentials. Relativistic effects (ZORA and spin-orbit coupling) and parallel implementations are available for most properties
Analysis
(The energy decomposition method in ADF allows for a detailed understanding of chemical bonding) ADF contains several unique analysis options, offering the possibility of gaining detailed understanding of the chemical problem at hand. These methods stress the underlying philosophy that the Kohn-Sham orbitals in DFT can be used for a ‘quantitative Molecular Orbital theory’. The ADF-GUI modules, such as ADFlevels and ADFview, make these analysis options readily accessible.
Accuracy and Efficiency
(Difference density for hydrogen molecules on a copper slab) ADF uses Slater-Type Orbitals (STO’s) as basis functions. These resemble the true atomic orbitals more closely than the more common Gaussian-Type Orbitals (GTO’s). Therefore, fewer STO’s than GTO’s are needed for a given level of accuracy. ADF has a database consisting of thoroughly tested basis set files, ranging in quality from single-zeta to quadruple-zeta basis sets with various diffuse and polarization functions. All-electron and frozen-core basis sets are available for all elements, including lanthanides and actinides. The frozen-core approximation can be used to considerably reduce the computation time for systems with heavy nuclei, in a controlled manner. In the BAND program, numerical atomic orbitals are used in addition to STO’s
BAND
(Chemisorption / chemical reactions on a metal surface) BAND is a periodic structure program for the study of bulk crystals, surface, and polymers.
ADF-GUI & BAND-GUIThe graphical user interface for ADF (ADF-GUI) supports fragment analysis to build complicated inorganic compounds. This is complemented by a dedicated graphical user interface for BAND (BAND-GUI).
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