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Re^5: Proposals for updating the manual

Richard
bonarlaw@liv.ac.uk


Thanks for correcting me on this - I've previously used both types of truncation but never understood which was the right one, since the results from a few tests (energies and structures of some closed-shell 3rd row TM complexes) were almost identical.  

BTW, do you know under what circumstances one really does need the H-term - open shells with high L valence functions perhaps ? (just guessing here..)

Richard


On Mon Jan 11 '10 10:19pm, Andrei V Scherbinin wrote
----------------------------------------------------
>I'm afraid such a truncation of G-H-term is not a correct procedure in general,
>and the results may be consistent only occasionally.

>A regular way to cut off the H harmonics from the ECP is as follows.

>The key idea is that one has to omit the (identically zero in the folow-up case!)
>H-harmonic term. Then the G-H-potential is the new isotropic (i.e. projector-free)
>G-potential, which should be subtracted from all the semilocal potentials corresponding
>to L < 4.

>I give just an example of Stuttgart RSC ECP for Ce atom, before and after the truncation:

>Before:

>CE-ECP GEN 28    5
> 1      ----- H POTENTIAL     -----
>      0.00000000  2        1.00000000
> 1      ----- S-H POTENTIAL   -----
>    580.08345700  2       20.13782900
> 1      ----- P-H POTENTIAL   -----
>    310.30283300  2       15.99848200
> 1      ----- D-H POTENTIAL   -----
>    167.81394400  2       14.97418700
> 1      ----- F-H POTENTIAL   -----
>    -49.39022900  2       23.40245500
> 1      ----- G-H POTENTIAL   -----
>    -21.33187900  2       16.57055300

>After:
>
>
>CE-ECP GEN 28    4
> 1      ----- G POTENTIAL     -----
>    -21.33187900  2       16.57055300
> 2      ----- S-G POTENTIAL   -----
>    580.08345700  2       20.13782900
>     21.33187900  2       16.57055300
> 2      ----- P-G POTENTIAL   -----
>    310.30283300  2       15.99848200
>     21.33187900  2       16.57055300
> 2      ----- D-G POTENTIAL   -----
>    167.81394400  2       14.97418700
>     21.33187900  2       16.57055300
> 2      ----- F-G POTENTIAL   -----
>    -49.39022900  2       23.40245500
>     21.33187900  2       16.57055300

>The latter one may be safely inserted into the $ECP group
>for both US GAMESS and Firefly.
>
>
>
>On Sun Jan 10 '10 3:33am, Richard wrote
>---------------------------------------
>>I don't know about gamess-us, but one thing you can try is running a similar job in Firefly with and without the G-H term (reducing lmax by 1 in the latter case). If the differences are small enough, then it might be alright to just use the ECP without the G-H term in gamess-us.

>>Richard
>>
>>
>>On Fri Jan 8 '10 9:02pm, sanya wrote
>>------------------------------------
>>>Did I get it right that H-ECPs will work automatically in the next versions of Firefly? Great!
>>>By the way, what is the situation with H-ECPs in GAMESS-US? I couldn't find anything from the manual...

>


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