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gabrielasd / pyeom

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EOM data #71

Open PaulWAyers opened 2 years ago

PaulWAyers commented 2 years ago

Generate EOM data for the various different sorts of methods we have. It would be useful to attempt to compare to experiment and/or full-CI.

A natural starting point is the Be atom with a relatively large basis set.

  1. compare energies.
  2. compare wavefunctions or DMs. You can compute cos^2 between CI coefficents or DMs. E.g.

$$ (\sum_n c_n^{EOM} c_n^{FCI} )^2 $$

$$ \frac{(Tr[1DM^{EOM} \cdot 1DM^{FCI}] )^2}{Tr[1DM^{EOM} \cdot 1DM^{EOM}]Tr[1DM^{FCI} \cdot 1DM^{FCI}]} $$

PaulWAyers commented 2 years ago

A follow-up that would not be too hard, but might still be informative, would be the BeH2 dissociation curve (insertion of Be into H2).

It would be useful to check these for HF, FCI, and DOCI.

PaulWAyers commented 2 years ago

If we were going to try one diatomic, BF (or even LiF) would be desirable. But LiH dissociation would be another 4-electron case so FCI data would be accessible.

PaulWAyers commented 2 years ago

Important to add diffuse function to Li, H, and Be.

PaulWAyers commented 2 years ago

H4, with ANO-2s+diffuse (or 6-31G++).