ACES II User manual version 2.7.0 (PDF) - Quantum Theory Project

Specifies whether the gradient formulation assumes that the perturbed orbitals are notthose in which the Fock matrix is diagonal (=STANDARD). =CANONICAL meansthat the perturbed orbitals are assumed to be canonical. This keyword must be setto CANONICAL in gradient calculations with methods that include triple excitations(i.e., MBPT(4), CCSD[T], CCSD(T), and QCISD(T)).8.1.9 SCF: generalSCF TYPE = (handle) HFSwitches the SCF code between the standard Hartree-Fock program (=HF) and theKohn-Sham DFT program (=KS). If SCF TYPE=KS, then the KS-DFT program generatesthe SCF reference and requires separate namelists (viz. *VSCF and *INTGRT).FOCK = (handle) PKSpecifies the algorithm for constructing the Fock matrix in SCF calculations. =PKuses the PK-supermatrix approach while =AO constructs the matrix directly from theAO integrals. In general, PK is faster but results in considerable use of disk spacewhen out-of-core algorithms are required.CHECK SYM = (handle) OVERRIDESpecifies the action taken when the density matrix does not transform as the totallysymmetric irreducible representation of the full molecular point group. =NORMALterminates the run if the molecule is nonlinear, while =OVERRIDE allows the job tocontinue but prints a warning message. Nonsymmetric density matrices result fromcalculations on electronically degenerate states or from broken-symmetry SCF solutions.Often, such calculations do not give meaningful results and inexperienced usersare encouraged to use CHECK SYM=NORMAL in their calculations on nonlinearmolecules. For Π, ∆, Φ, ... states of linear molecules, however, meaningful calculationscan still be performed even though the density matrix is not symmetric.SCF PRINT = (integer) 0[This keyword is currently not used but exists for future compatibility.]8.1.10 SCF: orbital controlGUESS = (handle) MOREADSpecifies where the initial SCF eigenvectors are read from. The HF-SCF executablechecks multiple places for pre-existing orbitals, but this keyword can override thatlogic.49