Basic Keywords

WFN = string

This may be casscf or rasscf.

REFERENCE = string

Any of the references allowed by detci should work (i.e., not uhf), but there should be no reason not to use rhf.

DERTYPE = string

At present, only energies (none) are supported; future releases will implement gradients (first).

CONVERGENCE = integer

Convergence desired on the orbital gradient. Convergence is achieved when the RMS of the error in the orbital gradient is less than 10**(-n). The default is 4 for energy calculations and 7 for gradients. Note that this is a different convergence criterion than for the detci program itself. These can be differentiated, if changed by the user, by placing the CONVERGENCE keywords within separate sections of input, such as detcas: ( convergence = x ).

ENERGY_CONVERGENCE = integer

Convergence desired on the total MCSCF energy. The default is 7.

RESTRICTED_DOCC = (integer array)

Should be in psi:() or default:() sections of input. The number of lowest energy doubly occupied orbitals in each irreducible representation from which there will be no excitations. These orbitals are optimized in the MCSCF. The Cotton ordering of the irredicible representations is used. The default is the zero vector.

RESTRICTED_UOCC = (integer array)

Should be in psi:() or default:() sections of input. The number of highest energy unoccupied orbitals in each irreducible representation into which there will be no excitations. These orbitals are optimized in the MCSCF. The default is the zero vector.

FROZEN_DOCC = (integer array)

Should be in psi:() or default:() sections of input. The number of lowest energy doubly occupied orbitals in each irreducible representation from which there will be no excitations. These orbitals are literally frozen and are not optimized in the MCSCF; usually one wishes to use RESTRICTED_DOCC instead. The current version of the program does not allow both RESTRICTED_DOCC and FROZEN_DOCC. Should be in psi:() or default:() sections of input. The Cotton ordering of the irredicible representations is used. The default is the zero vector.

FROZEN_UOCC = (integer array)

Should be in psi:() or default:() sections of input. The number of highest energy unoccupied orbitals in each irreducible representation into which there will be no excitations. These orbitals are literally frozen and are not optimized in the MCSCF; usually one wishes to use RESTRICTED_UOCC instead. The current version of the program does not allow both RESTRICTED_UOCC and FROZEN_UOCC. Should be in psi:() or default:() sections of input. The default is the zero vector.

NCASITER = integer

Maximum number of iterations to optimize the orbitals. This option should be specified in the DEFAULT section of input, because it needs to be visible to the control program PSI. Defaults to 20.

AVERAGE_STATES = (integer array)

This gives a list of what states to average for the orbital optimization. States are numbered starting from 1.

PRINT = integer

This option determines the verbosity of the output. A value of 1 or 2 specifies minimal printing, a value of 3 specifies verbose printing. Values of 4 or 5 are used for debugging. Do not use level 5 unless the test case is very small (e.g. STO H$_2$O CISD).