Firefly and PC GAMESS-related discussion club



Learn how to ask questions correctly

Re^4: Proposals for updating the manual

Andrei V Scherbinin
andrei.scherb@gmail.com

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...

[ Previous ] [ Next ] [ Index ]           Mon Jan 11 '10 10:19pm
[ Reply ] [ Edit ] [ Delete ]           This message read 799 times