(a) The evaluation of 1 and 2-electron integrals over contracted cartesian gaussian basis functions of type s, p , d , or f. The program can also use pseudopotentials of both the Huzinaga and the Hay-Wadt forms.
(b) SCF energy calculations for closed shell, open-shell, UHF and generalised open-shell techniques. The algorithms used can be either 'in core', or conventional or 'direct' according to the size of the calculation.
(c) calculation of 1-electron properties, including distributed multipoles.
(d) calculation of the gradients of the SCF energy.
(e) use of the gradients for automatic geometry optimization, the location of saddle points and for the calculation of force constants by numerical differentiation. There is a choice of two optimization algorithms.
(f) transformation of the integrals from the atomic orbital to the molecular orbital basis. A 'semi-direct' transformation exists for large cases.
(g) Moller-Plesset perturbation theory calculations to fourth order in the energy and second order in the 1-electron properties. The Moller-Plesset routines are closed-shell, UHF or ROHF. The second-order routines can be conventional or direct.
(h) coupled Hartree-Fock calculations of polarizabilities, including the frequency dependence, excitation energies, magnetizabilities and nmr shielding constants.
(i) coupled Hartree-Fock calculations of the perturbation due to nuclear displacements.
(j) calculation of the dipole and quadrupole moment derivatives.
(k) calculation of the second derivatives ( force constants) of the energy by analytic methods.
(l) analytic calculations of polarizability derivatives.
(m) calculation of infrared and Raman intensities, and the study of vibrational circular dichroism.
(n) calculation of MP2 gradients, dipole moment derivatives, polarizabilities and force constants using analytic algorithms.
(o) spin-projected UHF MP2 energies
(p) frequency dependent hyperpolarisabilities.
(q) a variety of CI and coupled-cluster based methods.
(r) a variety of density functional methods, both closed-shell and open-shell, and including analytic gradients and force constants, and nmr shielding. The functionals available included local density and gradient corrected methods, and functionals with partial SCF exchange.
(s) calculation of distributed multipoles and polarisabilities by numerical integration.
(t) Intermolecular perturbation theory.
(u) Finite field calculations using external fields, field gradients and lattices.