H2 @ direct CCSD(T)/6-31G* fails

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Unique to diatomic hydrogen.

Fails with direct CCSD(T), reports Out Of Memory error irrespective of generous allocation.
Succeeds using TCE.
Succeeds using 6-31G** or larger Pople basis set.

Test script reproduces failure:

start H2
#memory 10 gb
print all

title "H2"
charge 0

geometry units angstroms print xyz
symmetry C1
H -0.372 0.0 0.0
H 0.372 0.0 0.0
end

basis
H library 6-31G**
end

#succeeds
task ccsd(t) energy

unset "basis:*"

basis
H library 6-31G*
end

# FAILS
task ccsd(t) energy

-drh

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Thanks for the bug report.

It might be a memory leak.
Edited On 10:26:09 AM PDT - Fri, Jul 17th 2015 by Edoapra

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fix checked into the svn repository

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Quote:Edoapra Jul 17th 1:14 pm
fix checked into the svn repository
(*blink!*)
That was quite fast.
Thank you very much.

-drh

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CCSD is an exact wavefunction for a two-electron system. The (T) contribution should be zero. Why are you trying to run this?

Anyways, I'm glad to see that Edo fixed the issue already.

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Quote:Jhammond Nov 28th 10:45 pm
CCSD is an exact wavefunction for a two-electron system. The (T) contribution should be zero. Why are you trying to run this?

Simple malice.

(*cough!*)

The H and H2 energies are first test cases in the Gaussian-N composite thermochemical methods, even before water, ammonia, and the G2, G3 test suites.

In the G3(MP2) and G4(MP2) methods we got working in NWChem, the post-HF and task statements are general and under python control. The H2 run aborted with an unrelated failure message instead of a modest warning like "not enough electrons for non-iterative triples, (T) correlation = 0.0", i.e., a graceful failure.

The G3(MP2) and G4(MP2) pythonic Nwchem code is currently languishing on Github at
[https://github.com/mattbernst/composite-thermochemistry-nwchem]

It's still manually installed with all that implies about finish level.

-drh


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