Editing NEEMP:files

'''NEEMP''' uses 3 types of input files. '''SDF''' file contains structural information about the molecules, i.e. positions of atoms and bonding information; '''CHG''' file contains previously computed ''ab-initio'' charges; and '''PAR''' file stores the list of '''NEEMP''''s EEM parameters. 

The following sections illustrate the details of each file type. Examples of these input files can also be found in the ''examples'' directory.

=SDF file=
[[File:sdf_file.png | thumb | 400px | right| '''''Figure 8:''''' V2000 MOL record extracted from '''SDF''' file ''examples/set01.sdf''. Note the atomic coordinates and bond connections blocks and the ''$$$$'' line marking the end of the record.]]

'''SDF''' file contains MOL records for each molecule separated by line consisting only of four dollar signs, i.e. $$$$. Each MOL record can be either in '''V2000''' or '''V3000''' version. The latter one is required for molecules with more than 999 atoms or bonds. For further reference on MOL format, see specification: [http://c4.cabrillo.edu/404/ctfile.pdf CTFile formats].

For convenience '''NEEMP''' has a support for reading '''SDF''' files which are compressed using ''gzip'' method. This might be useful when working with large databases of molecules.
<br style="clear:both" />

=CHG file=

Each record (charges for one molecule) in the '''CHG''' file consists of 3 parts. First line is the name of the molecule (it must be the same as in the '''SDF''' file to pair the charges to the structural information), second line contains number of atoms N and then N lines for each atom with its charges:

<pre>
My dummy molecule name
5
     1  C   -0.921539
     2  H   -0.507788
     3  H   -0.565167
     4  H   -0.200822
     5  H    0.110252

</pre>

Note that only the third column (the actual charge) is read, the first two are silently ignored. This implies that the order of the atoms in the structure and charge records must be the same to get a perfect pairing.

Every other record is separated from the previous one by a blank line.

=PAR file=

'''PAR''' file is used for storing EEM parameters. It's a simple XML file of the following form. All fields are pretty self-explanatory. The ''AtomType'' parameter corresponds to the <code>--atom-types-by</code> option.

<pre>
<?xml version="1.0"?>
<ParameterSet>
  <Parameters AtomType="ElemBond" Kappa="0.1976">
    <Element Name=" O">
      <Bond Type="1" A="2.6730" B="0.4091"/>
      <Bond Type="2" A="2.7759" B="0.6434"/>
    </Element>
    <Element Name=" C">
      <Bond Type="2" A="2.4880" B="0.2348"/>
      <Bond Type="1" A="2.4787" B="0.2722"/>
    </Element>
    <Element Name=" H">
      <Bond Type="1" A="2.3827" B="0.5701"/>
    </Element>
    <Element Name=" N">
      <Bond Type="2" A="2.5440" B="0.2370"/>
      <Bond Type="1" A="2.5370" B="0.2526"/>
    </Element>
    <Element Name=" S">
      <Bond Type="2" A="2.4945" B="0.1454"/>
      <Bond Type="1" A="2.4050" B="0.3687"/>
    </Element>
  </Parameters>
</ParameterSet>
</pre>