| Keyword | Effect |
|---|
Triples none|st|pt|f | Perturbative-triples model (CCSD(T) uses st) |
FreezeCore | Correlate only valence electrons |
DropVirt f | Drop virtual orbitals below threshold |
Conv N | Convergence threshold = 10⁻ᴺ |
MaxIter N | Max CC iterations (default 50) |
Diis | Enable CC-DIIS |
DiisStart N | First iteration to use DIIS (default 2) |
Shift f | Static level shift for amplitude update |
Read file | Read amplitudes from checkpoint |
Skip tokens | Comma-separated skip tokens |
Acc2E N | ERI threshold override for CC |
Brueckner | Brueckner coupled-cluster (BCCD/BCCD(T)) |
Triples | Description |
|---|
none | CCSD only |
st | Standard CCSD(T) (non-iterative) |
pt | CCSD(2)_T (iterative) |
f | Full CCSDT (iterative) |
See CC Section for detailed descriptions and examples.