[cclib-devel] g09 fragment guesses

[Adam T. <ate...@gm...>]

Hi all,

One of my friends from a former lab found a bug in the Gaussian parser in a
calculation involving anti-ferromagnetic coupling calculations set up via
the guess keyword (see example at
http://www.gaussian.com/g_tech/g_ur/k_guess.htm). The output is similar to
the counterpoise/BSSE calculations, although I think it also prints
aooverlaps and mocoeffs for each fragment as well as the entire molecule
whereas the counterpoise calculations do not. I've committed a few fixes to
trunk, but I have a few follow-up questions:

1) Shall I run the Fe2S2 example (or something similar) as our regression
file? Sam's files are hundreds of MB, and I think a prototypical example
would be best. ORCA also handles these systems well, and while I think it
parses such calculations fine, we probably should also have a regression
file for this parser too.

2) Do we want to parse the fragment wavefunction info as well? It would
make our parser that much more robust, although it adds layers of
complexities. If so:
2a) Create new attributes as necessary (fmoenergies, fmocoeffs, fhomos,
etc.)? We'd also want something analogous to fooverlaps and fonames (ADF),
but here it'd have to be a lists instead of the normal items.
2b) Or append to the current fmoenergies, fmocoeffs, etc? Then [0]/[1]
corresponds to molecule alpha/beta, [2]/[3] corresponds to fragment 1
alpha/beta, [4]/[5] corresponds to fragment 2 alpha/beta, and so on. (I
don't see any reasons these calculations would have restricted fragments).

Cheers,

Adam