8.3 Mopac calculation
This dialog window allows to run the Mopac
semi-empirical calculation. Press the Run button to start the calculation,
otherwise press Cancel to close the dialog. Please note that the Mopac
executables are included in the standard VEGA ZZ package. If you want use another
Mopac version, you must
replace the included executable placed in the VEGA ZZ installation folder with the new one.
When you press Start, a file requester is shown in order to select the output
file. Mopac runs in background and VEGA ZZ remains fully functional. When the calculation
ends without errors, the processed structure is automatically reloaded. To abort a
Mopac calculation, use the Task Manager.
8.3.1 Parameter fields
With these fields you can specify the type of calculation (AM1, MINDO/3, MMDO, PM3), the total charge (if the pre-calculated charge is wrong) and the extra keywords (Other field). The default parameters are AM1 and the pre-calculated total charge.
8.3.2 Switches
They are the main switches for Mopac calculation. To understand what they mean, please read the Mopac Manual. The MMOK switch is checked automatically if the molecule has a peptidic bond.
8.3.3 Limits
VEGA ZZ includes two versions of Mopac 7.01-4: Mopac_50_100.exe (max 50 heavy atoms and max 100 hydrogens) and Mopac_100_200.exe (max 100 heavy atoms and max 200 hydrogens). The two executables are selected automatically by VEGA ZZ for a balanced use of the hardware resources. No more than 300 atoms (100 heavy atoms + 200 hydrogens) can be used by VEGA ZZ in Mopac calculations.