MOPAC COSMO calculation
***********************

Here it is described briefly how to make MOPAC COSMO result files.

The simplest way is to use AMSinput. Draw the molecule using AMSinput,
and save the .ams file. Select **Right Panel → MOPAC → Solvation
method → COSMO-CRS**. Select 362 for NSPA. Press Run to run the MOPAC
calculation. A .coskf file will be saved that can be used as input in
COSMO-RS calculations.

In AMS2019 AMSinput uses the MOPAC engine, which is part of the AMS
driver. Note that this is different than in AMS2018 and before. In the
Atoms block key in the AMS driver part of the input one puts the
coordinates of the molecule. The main input keys for the AMS driver
and the MOPAC engine are:

   $AMSBIN/ams << eor
   Task GeometryOptimization
   System
       Atoms
          ....
       End
   End

   Engine MOPAC
       Solvation
           Enabled Yes
           NSPA 362
           Solvent
               Name CRS
           End
       End
   EndEngine

   eor

The use of the solvent CRS makes the MOPAC engine to create a .cos
file, which is converted to a .coskf file by  $AMSBIN/cosmo2kf

   cosmo2kf file.cos file.coskf

Note that this is automatically done if one uses AMSinput.

Compared to the default ADF COSMO-RS values a few  COSMO-RS parameters
were reoptimized for MOPAC PM6 COSMO result files to improve the
calculation of a number of partition coefficients, when compared to
experimental values. Note that MOPAC is a semi-empirical quantum
chemistry program, whereas ADF is based on density functional theory
(DFT). Thus the MOPAC COSMO result files will not be of the same
quality as the ADF COSMO result files.
