The Cambridge Analytic Derivatives
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
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
5. The usual sort of properties, ie multipole
moments , distributed multipole analyis,
NMR shielding constants (LORG algorithm), infra-red
intensities, Raman intensities, VCD intensities,
frequency dependent polarisabilities and
hyperpolarisabilities, excitation energies by RPA method,
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
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 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
Contact Aron Cohen by email: email@example.com.