Firefly and PC GAMESS-related discussion club

 
Learn how to ask questions correctly  
 
 

 

Alex Granovsky
gran@classic.chem.msu.su

with Firefly, semi-empirical calculations do not print
information on the basis set in use. My guess is that
this is why ChemCraft refuses to plot them.

This limited printout cannot be fixed using current versions
of Firefly.

These runs use minimal valence-only Slater-type basis sets.
These "basis sets" are a bit strange and are more the fiction
than the real basis sets. For instance, in semi-empirical SCF
calculations the overlap matrix is always assumed to be the
unit matrix, while if computed using basis set definition,
it is a non-unit matrix. Due to fictitious nature of these
basis sets, it could be difficult to interpret visualized
orbitals.

Kind regards,
Alex Granovsky

On Tue Mar 12 '13 5:54pm, romm wrote
------------------------------------
>Hello, developers and users of Firefly.

>We have some problems with analyze information about Molecular orbitals from output file after calculation in Firefly program using semi-empirical basis AM1 and PM3 (used also by Mopac program).
>Chemcraft gave us error message "Could not read MO energies from the file", however data block "EIGENVECTORS" have been presented in output file, as well as used basis set 5-31G.
>On the other hand for ab initio calculation of simple example task with basis 5-31G information of MO extraction was occurred correctly with help of Chemcraft program.

>We need that for calculate a big system (around 800 atoms) so we can not even use basis 3-21G.

>Also we try Gabedit, wxMacMolPlt to visualise MO, calculated by use PM3 basis in Firefly; but all of them can not be solve that problem.

>Is it possible to solve this problem?
>What programs we need to use to analyse information about MO and their visualisation?
>We would be grateful for any information on the matter.