Requests a Quadratic CI calculation including single and double substitutions with a triples contribution to the energy added [Pople87].
Saves the converged amplitudes in the checkpoint file for use in a subsequent calculation (e.g., using a larger basis set). Using this option results in a very large checkpoint file, but also may significantly speed up later calculations.
Reads the converged amplitudes from the checkpoint file (if present). Note that the new calculation can use a different basis set, method (if applicable), etc. than the original one.
All frozen core options are available with this keyword; a frozen core calculation is the default. See the discussion of the FC options for full information.
Specifies the maximum number of cycles. The default is 50.
Analytic energies and gradients for QCISD, numerical gradients for QCISD(T), and numerical frequencies for all methods.
The predicted energy from a QCISD calculation appears in the output in the final QCISD iteration:
DE(CORR)= -.54999890D-01 E(CORR)= -.7501966245D+02
When QCISD(T) is specified, the preceding output is followed by the energy including the non-iterative triples contribution:
Last updated on: 15 September 2016. [G16 Rev. A.03]