Re: [cclib-devel] etsecs conversions

[Noel O'B. <bao...@gm...>]

On 27/03/07, Karol Langner <kar...@kn...> wrote:
> OK, now all the parsers read in the "raw" coefficients - which mean the jaguar
> parser divides them by sqrt(2.0). I added tests for etenergies and etsecs to
> check across parsers, basing on the values from the GAMESS test (water for
> CIS/STO-3G - see my most recent commit).
>
> The values of etenergies look good - although I had to give a tolerance of
> 50cm-1 (is that alot?).
Experimentally, we typically use nm, and the conversion from cm-1 to
nm (1E7/x = y) has different 'sizes' at different wavelengths. At
around 300nm (which is where I expect these transitions are...the
typical 'organic chemistry' range), 50cm-1 is less than 1 nm, which is
more than acceptable. :-)

> But, there seems to be a problem related to the excitation coefficients (which
> need a tolerance above 0.0005, by the way). Namely, some of the coefficients
> printed by Gaussian have different signs than the ones printed by GAMESS
> (observe also that the ones given by Jaguar are consistently with an extra
> minus compared to GAMESS). This is probably due to the symmetry type (A1, B1,
> A2, ...). I don't know what the relation is, however, and we should
> standardize this. Any ideas? Notice that the appropriate new test in
> testCI.py fails.
As discussed in the other thread, I think we should ignore the signs
for the purposes of testing. Although I wonder is this related to
alpha/beta? Should both the alpha and beta orbitals for the same
transition have the same sign?

> Karol
>
> --
> written by Karol Langner
> Tue Mar 27 19:45:33 CEST 2007
>