Package: nwchem (7.0.2-1)

Højtydende programmer til beregninger i kemi

NWCHem er en programpakke til foretage beregninger i kemi. Den tilbyder metoder, der kan skalere i både evnen til effektiv håndtering af store problemer i videnskabelige beregninger inden for kemien, samt evnen til at gøre brug af parallelle beregningsressourcer fra højtydende parallel- supercomputere til konventionelle klynger af arbejdsstationer.

NWChem kan håndtere:

 * Molekylære, elektroniske strukturmetoder med brug af gaussisk
   basisfunktioner til molekylærberegninger med høj præcision
 * Elektronisk strukturmetoder til pseudopotentialer for planbølger til
   beregning af molekyler, væsker, krystaller, overflader, halvledere eller
   metaller
 * Ab-initio og klassisk simulering af molekylære dynamikker
 * Blandede, klassiske kvantum-simuleringer
 * Parallel skalering til tusinder af processorer

(Den efterfølgende beskrivelse af egenskaber bevares på engelsk).

 * Molecular electronic structure methods, analytic second derivatives:
  - Restricted/unrestricted Hartree-Fock (RHF, UHF)
  - Restricted Density Functional Theory (DFT) using many local,
    non-local (gradient-corrected) or hybrid (local, non-local, and HF)
    exchange-correlation potentials
 * Molecular electronic structure methods, analytic gradients:
  - Restricted open-shell Hartree-Fock (ROHF)
  - Unrestricted Density Functional Theory (DFT)
  - Second-order Moeller-Plesset perturbation theory (MP2), using RHF
    and UHF reference
  - MP2 with resolution of the identity approximation (RI-MP2)
  - Complete active space SCF (CASSCF)
  - Time-Dependent Density Functional Theory (TDDFT)
 * Molecular electronic structure methods, single-point energies:
  - MP2 spin-component scaled approach (SCS-MP2)
  - Coupled cluster singles and doubles, triples or pertubative triples
    (CCSD, CCSDT, CCSD(T)), with RHF and UHF reference
  - Configuration interaction (CISD, CISDT, and CISDTQ)
  - Second-order approximate coupled-cluster singles doubles (CC2)
  - State-specific multireference coupled cluster methods (MRCC)
    (Brillouin-Wigner (BW-MRCC) and Mukherjee (Mk-MRCC) approaches)
 * Further molecular electronic structure features:
  - Geometry optimization including transition state searches, constraints
    and minimum energy paths (via the Nudged Elastic Band (NEB) and Zero
    Temperature String methods)
  - Vibrational frequencies
  - Equation-of-motion (EOM)-CCSD, EOM-CCSDT, EOM-CCSD(T), CC2,
    Configuration-Interaction singles (CIS), time-dependent HF (TDHF) and
    TDDFT, for excited states with RHF, UHF, RDFT, or UDFT reference
  - Solvatisation using the Conductor-like screening model (COSMO) for RHF,
    ROHF and DFT, including analytical gradients
  - Hybrid calculations using the two- and three-layer ONIOM method
  - Relativistic effects via spin-free and spin-orbit one-electron
    Douglas-Kroll and zeroth-order regular approximations (ZORA) and
    one-electron spin-orbit effects for DFT via spin-orbit potentials
 * Pseudopotential plane-wave electronic structure:
  - Pseudopotential Plane-Wave (PSPW), Projector Augmented Wave (PAW)
    or band structure methods for calculating molecules, liquids,
    crystals, surfaces, semi-conductors or metals
  - Geometry/unit cell optimization including transition state searches
  - Vibrational frequencies
  - LDA, PBE96, and PBE0 exchange-correlation potentials (restricted and
    unrestricted)
  - SIC, pert-OEP, Hartree-Fock, and hybrid functionals (restricted and
    unrestricted)
  - Hamann, Troullier-Martins and Hartwigsen-Goedecker-Hutter norm-
    conserving pseudopotentials with semicore corrections
  - Wavefunction, density, electrostatic and Wannier plotting
  - Band structure and density of states generation
 * Car-Parrinello ab-initio molecular dynamics (CPMD):
  - Constant energy and constant temperature dynamics
  - Verlet algorithm for integration
  - Geometry constraints in cartesian coordinates
 * Classical molecular dynamics (MD):
  - Single configuration energy evaluation
  - Energy minimization
  - Molecular dynamics simulation
  - Free energy simulation (multistep thermodynamic perturbation (MSTP) or
    multiconfiguration thermodynamic integration (MCTI) methods with
    options of single and/or dual topologies, double wide sampling, and
    separation-shifted scaling)
  - Force fields providing effective pair potentials, first order
    polarization, self consistent polarization, smooth particle mesh Ewald
    (SPME), periodic boundary conditions and SHAKE constraints
 * Mixed quantum-classical:
  - Mixed quantum-mechanics and molecular-mechanics (QM/MM) minimizations
    and molecular dynamics simulations
  - Quantum molecular dynamics simulation by using any of the quantum
    mechanical methods capable of returning gradients.

Tags: Field: Chemistry, Role: Program

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