PARAM input data file

The PARAM input data files control a parameter optimization calculation, and control how surveys are run.

Structure of an input data set for parameter optimization

Data files have names, in the format <file>.dat. An example of a PARAM data set, "br.dat", is given in the following box:

Comment       *
Comment       * Optimize PM7 parameters for a single element
Comment       *
Control   Line 1   set=..\normal\all_ref_data.txt ref=N:\;R:\;L:\ params=..\new\params.txt;br.rp
Parameters   Line 2   (br)(All)
End of parameters   Line 3   end
ref. data file names   Line 4    

Like a MOPAC data set, a PARAM data set can include comment lines.  These are lines that start with an asterisk (*).  Such lines are completely ignored by PARAM.

Line 1: PARAM Keywords that control the type of job. In the example, three keywords are used, SET, REF, and PARAMS.  These keywords indicate that:

The set of reference data file names is in the file all_ref_data.txt, stored in folder ..\normal.
The reference data files themselves are in folders N:\, R:\, and L:\.  This is also the order of searching.
The default PM6 parameters are to be replaced using parameters in file params.txt. The file params.txt is in folder ..\new
The modified parameters are to be replaced by the parameters in file br.rp.  This file is in the current folder.

Since no method was specified, the approximations and initial set of parameters are those of PM6.  This is the default.

Line 2: The parameters to be optimized. Here, all parameters for Bromine are to be optimized.

Line 3: The terminator for the list of parameters to be optimized.

Line 4: Blank here, but can contain the set of reference data file names.

 

Structure of an input data set for running a survey

Comment       *
Comment       * Survey the new method for elements H C N and O
Comment       *
Control   Line 1   set=..\normal\all_ref_data.txt ref=N:\ params=..\new\params.txt only survey
Parameters   Line 2   (H C N O)(USS)
End of parameters   Line 3   end
ref. data file names   Line 4    

Line 1: PARAM Keywords that control the type of job. In the example, five keywords are used, SET, REF, PARAMS, ONLY and SURVEY.  These keywords indicate that:

The set of reference data file names is in the file all_ref_data.txt, stored in folder ..\normal.
The reference data files themselves are in the folder N:\.  No other folders are used, as the survey is over normal compounds.
The default PM6 parameters are to be replaced using parameters in file params.txt. The file params.txt is in folder ..\new
only: means that only reference data that contains one or more elements marked for optimization are to be used in the survey.
survey:  means "run a survey" not a parameter optimization.

Since no method was specified, the approximations and initial set of parameters are those of PM6.  This is the default.

Line 2: The set of elements to be used in the survey, here hydrogen, carbon, nitrogen, and oxygen. It is sufficient to use the parameter USS.  In a survey, these parameters will not be modified. They are only used as a way of indicating elements.

Line 3: The terminator for the list of parameters to be optimized.

Line 4: Blank here, but can contain the set of reference data file names.