| 8:58:00 AM PST - Wed, Dec 10th 2014 |
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Quote:Mernst May 18th 8:33 amIn src/tce/tce_input.F I see that there are handlers for "qcisd(t)" and "cr-qcisd(t)". I took QA/tests/tce_h2o/mp4sdq_h2o.nw and replaced
tce
mbpt4(sdq)
end
with
tce
qcisd(t)
end
and the modified input file appeared to run successfully, i.e. it produced a number that looked reasonable and didn't crash during execution.
But I don't know if it is really ready for use since the manual doesn't mention QCISD(T):
http://nwchemgit.github.io/index.php/TCE
I am interested in implementing the Gaussian-n composite thermochemical methods. I want to be able to treat open shell molecules so the implementations in GAMESS and Psi4 are currently inadequate; both require RHF reference functions for their QCISD(T) functionality. If there's something weird about the QCISD(T) functionality implemented through the TCE I don't have a second program to double-check calculations on open shell molecules using it.
That code might be correct. I recall that (T) is the same for QCISD and CCSD. It should be valid to run the (T) code with QCISD amplitudes.
I am surprised that QCISD(T) for open-shell systems cannot be verified via CFOUR. Can you verify this?
In any case, QCISD(T) only has a quadratic singles term and thus I think CCSD(T), which has higher-order singles terms, should be much more accurate for open-source systems. QCISD(T) for open-shell and multi-reference systems is a known problem in the literature.
In the event you find an error in NWChem, please contact me and I will try to debug the issue. My email address is found on http://jeffhammond.github.io/.
Best,
Jeff
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