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The following table contains the keywords that
invoke additional computations. Terms marked
with an asterisk (*) appear in the *.out file.
Keyword
CIS
Description
UV absorption energies*
NOTE: Performs C.I. using only the
first excited Singlet states and does not
include the ground state. Use MECI to
print out energy information in the *.out
file.
FORCE Vibrational Analysis *
NOMM
NOTE: Useful for determining zero
point energies and normal vibrational
modes. Use DFORCE to print out
vibration information in *.out file.
No MM correction
NOTE: By default, MOPAC
performs a molecular mechanics (MM)
correction for CONH bonds.
Keyword
Description
T = n [M,H,D] Increase the total CPU time
allowed for the job.
NOTE: The default is 1h (1 hour) or
3600 seconds.
Specifying the
Electronic
Configuration
MOPAC must have the net charge of the molecule
in order to determine whether the molecule is open
or closed shell. If a molecule has a net charge, be
sure you have either specified a charged atom type
or added the charge.
CS MOPAC 2002 supports “sparkles”– pure ionic
charges that can be used as counter-ions or to form
dipoles that mimic solvation effects.
You can assign a charge using the Text Building
tool or by specifying it in MOPAC:
To add the charge to the model:
PI
PRECISE
Resolve density matrix*
NOTE: Resolve density matrix into
sigma and pi bonds.
Increase SCF criteria
NOTE: Increases criteria by 100
times. This is useful for increasing the
precision of energies reported.
1. Click the Text Building tool.
2. Click an atom in your model.
3. Type a charge symbol.
For example, click a carbon and type “+” in a
text box to make it a carbocation.The charge is
automatically sent to MOPAC when you do a
calculation.
To specify the charge in MOPAC:
1. From the Calculations menu, point to MOPAC
Interface and choose a computation.
The MOPAC Interface dialog box appears.
168•MOPAC Computations
CambridgeSoft
Specifying the Electronic Configuration