Summary of the main features of Cadpac

to 255 basis functions)

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

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 polarisabilities.

1. Closed shell energies for : CISD, CEPA, ACPF, QCISD, QCISD(T), CCD, BD and BD(T) 2. Analytic gradients for BD and BD(T)

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 added1) Intermolecular perturbation theory (IMPT) 2) Distributed multipole moments and polarisabilities by numerical integration 3) Distributed polarisabilities by the LeSueur-Stone algorithm

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## Contact Aron Cohen by email: ajc54@cam.ac.uk.

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