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##

24.1 Coupled-cluster, CCSD

The command `CCSD` performs a closed-shell coupled-cluster calculation.
Using the `CCSD(T)` command, the perturbative contributions of
connected triple excitations are also computed.

If the CCSD is not converged, an error exit will occur if triples are requested.
This can be avoided using the `NOCHECK` option:

`CCSD(T),NOCHECK`

In this case the (T) correction will be computed even if the CCSD did not converge.
Note: `NOCHECK` has no effect in geometry optimizations or frequency
calculations.

For further information on triples corrections see under RCCSD.

molpro@molpro.net 2015-04-20