PC GAMESS/Firefly-related discussion club

Learn how to ask questions correctly

Alex Granovsky
gran@classic.chem.msu.su

actually, your systems do not have any active electrons
to excite in MP2... and thus the number of active orbitals
is zero (and this means that E(MP2)=E(RHF)). There is no check
for this condition in the branch of MP2 code you are using
causing the divide by zero error - this will be fixed, however,
this code is now considered obsolete with method=1 code being
the best.

Hope this helps,
Alex Granovsky

On Thu Oct 15 '09 4:43pm, Vyacheslav wrote
------------------------------------------
>Hi,
>when I try to calculate energy of such cations as Na+, K+, Cs+ on МР2 level (see attached input file for example) I receive at the end of out files the next message:

>--------------------------   ----------------------------------------------
> RHF-MP2 ENERGY CALCULATION   PROGRAM WRITTEN BY M.DUPUIS,C.DANIEL,A.MARQUEZ
> --------------------------   ----------------------------------------------
> NCORE=   5     NOCC=    5     NAOS=   29
>*ERR* KO-04 integer divide by zero

>The same inputs with simple RHF or DFT instead of MP2 level have no any problems. What does it mean?
>Thanks in advance!
>