The Cambridge Analytic Derivatives Package

Summary of the main features of Cadpac
  • s,p,d and f basis function s.     Also, pseudopotentials for the transition elements.
  • a limit of 1000 basis functions and 100 atoms.   (though some correlated methods are limited

  •     to 255 basis functions)
  • SCF calculations
  • Møller-Plesset calculations
  • Other correlated calculations
  • Density Functional Theory
  • Additional Features
  • Downloads


    SCF calculations

    1. RHF, ROHF, UHF and GRHF scf types.  
       The SCF routines automatically choose in-memory
       algorithms for small cases, direct algorithms
       for large cases , and a conventional supermatrix form
       for intermediate cases.
    2. Analytic gradients for all SCF types.
    3. Analytic force constants for RHF, ROHF and GRHF
       Numerical force constants for UHF
    4  Location of stationary points (minima and
       transition structures)
    5. The usual sort of properties, ie multipole
       moments ,  distributed multipole analyis,
       polarisabilities, magnetisabilities,
       NMR shielding constants (LORG algorithm), infra-red
       intensities, Raman intensities, VCD intensities,
       frequency dependent polarisabilities and
       hyperpolarisabilities, excitation energies by RPA method,
       dispersion coefficients,
       effects of external fields, field-gradients and lattices.
       Some of these properties are 
       available for closed-shell systems only

    Møller-Plesset Calculations

    1. Closed-shell and open-shell energies and gradients.
       The open-shell cases can be either UHF or ROHF.   
       Energies are available for MP2, MP3 and MP4, gradients
       only for MP2 and MP3.  The MP2 routines adopt a direct (or
       semi-direct) approach for large cases.
    2. Analytic force constants, dipole moment derivatives
       and polarisabilities for closed-shell MP2 cases. 
       Open shell force constants by finite difference.
    3. Geometry optimisations etc.
    4. Properties : primarily charges and multipole moments, and

    Other correlated calculations

    1. Closed shell energies for :
    2. Analytic gradients for BD and BD(T)

    Density Functional Theory

      Closed-shell and open-shell (ROHF or UHF equivalents)
      energies and analytic gradients. 
      The energies and gradients are either 'conventional' or
      'direct' in the same way as the SCF programs.
       The DFT calculations can use either LDA or non-local
       functionals (B-LYP, B-P86, B-P91).  In addition various
       hybrid functionals including partial SCF exchange eg B3LYP
       and B3P91. The energies and gradients
       are evaluated to high precision, with gradients
       that are the exact derivatives of the potential energy
       surface.  Geometry optimisations can be done. Force
       constants are currently either by finite difference, or
       analytically (not not cases can be done analytically as yet).
       Symmetry (where available) is used in all calculations.
       The usual range of 1-electron properties are available.
       Polarisabilities, infra-red intensities etc are available
       for local and non-local DFT (though not for all functionals
       yet). Magnetic properties (NMR shielding) are also available. 
    Additional features recently added
    1) Intermolecular perturbation theory (IMPT)
    2) Distributed multipole moments and polarisabilities
       by numerical integration
    3) Distributed polarisabilities by the LeSueur-Stone
    4) Frequency dependent polarisabilities using DFT
     5) Excitation energies using DFT
     6) The HCTH, B97-1, PBE and PBE0 functionals.
     7) Excited state gradients using DFT


    For a limited period, free of charge:
    Silicon Graphics Origin series etc.
    IBM RS6000 series
    Compaq / DEC Alpha series
    Look here 

    Further Information

    Contact Aron Cohen by email: