6.18.1 Procedures for energy calculations

The wavefunction symmetry and spin can be modified using the variables SYMMETRY and SPIN, respectively. The number of electrons can be modified using the variable NELEC. SCF calculations are only done if no orbitals are available or if the symmetry or spin changed since the last SCF optimization. In CASPT and MRCI calculations the CASSCF is only done if the last optimized orbitals are not of MCSCF type.

runscf

Performs SCF calculation.

rundft

Performs DFT calculation. The functional can be specified using either the FUNCTIONAL or DFTNAME variable (default=B3LYP).

runmp2

Performs SCF and MP2 calculations.

runmp3

Performs SCF, MP2 and MP3 calculations.

runmp4

Performs SCF and MP2-MP4 calculations.

runmp4sdq

Same as runmp4, but without triples.

runccsd

Performs SCF and CCSD calculations. Uses RCCSD in open-shell cases.

runccsdt

Performs SCF and CCSD(T) calculations. Uses RCCSD(T) in open-shell cases.

runuccsd

Performs SCF and CCSD calculations. Uses UCCSD in open-shell cases.

runuccsdt

Performs SCF and CCSD(T) calculations. Uses UCCSD(T) in open-shell cases.

runbccd

Performs SCF and BCCD calculations (closed-shell only).

runbccdt

Performs SCF and BCCD(T) calculations (closed-shell only).

runqcisd

Performs SCF and QCISD calculations (closed-shell only).

runqcisdt

Performs SCF and QCISD(T) calculations (closed-shell only).

runcas

Performs SCF and CASSCF calculation. The wavefunctions for state averaged CASSCF calculations can be defined using the variables SYMMETRY, SPIN, STATE, WEIGHT, and NELEC.

caspt2

Performs SCF, CASSCF, and CASPT2 calculations. In case of state-averaged CASSCF reference functions (see runcas) the CASPT2 is performed for each state separately.

caspt3

As CASPT2, but also computes third-order energy.

runcaspt2

Same as caspt2.

runcaspt3

Same as caspt3.

runmrci

Performs SCF, CASSCF, and MRCI calculations. In case of state-averaged CASSCF reference functions (see runcas) the MRCI is performed for each state symmetry separately. Several states in the same symmetry are treated simultaneously. Transition moments are automatically computed between all states. However, these are not printed in the summary at the end of the output and must be extracted from the output or punch file.

runacpf

Performs SCF, CASSCF, and MR-ACPF calculations. At present, multiple-state MR-ACPF calculations are not possible.