This directory contains the following files:

README		this file

mopac6.sh	script to start off mopac6 job
mopac7.sh	script to start off mopac7 job
mopac93.sh	script to start off mopac93 job

mopacconv.f	Source of a conversion program to convert binary 
		graphics files (.gpt) to formatted graphics file (.fgpt)

mopac6.e	Mopac6 executable for the current machine.

Notes:

1. Run scripts.
---------------

Each of the run scripts has been set up according to our current
knowledge of the file names used for input and output for each of
the versions of Mopac. If you are using a version of Mopac6 other 
than the one supplied, you should check that the run script is
suitable for you version of the program.

Likewise, Mopac7 is available from QCPE in versions for SGand IBM  
machines. However the SG and IBM versions have very different ways of
handling the file names. If you are using a version other than these,
you should alter the run script so that, according to the value
returned by the 'uname' command (which gives the operating system) it
chooses one or other of the file name handlings supplied.

If you need to make any changes to the scripts, I recommend that you
always make copies of the original files. 

If you wish to make the changes in a different directory, this is 
possible. You will then have to edit the file applcomm.db, to change
the setting of the MOPACDIR variable to point to your new location.

2. Applcomm.db settings.
------------------------

The following variables need or may need to be set in the file
applcomm.db. If you are not sure about this, please consult the 
relevant section in the Cerius2 Installation Guide, and the introductory
chapter describing the Quantum Mechanics Workbench in the Cerius2 User
Manual.

MOPACDIR	Should always be set to the directory containing
		the runscripts for mopac6, mopac7, mopac93.
MOPAC6EXE	Should be set to the file name of the Mopac6 executable.
		This will be set on installation to the copy in this
		directory (see Note 5, below). If you have a different
		copy that you wish to use, you should chnage the
		setting in applcomm.db appropriately.
MOPAC7EXE	This should be set to the name of the Mopac7 executable
		for the machines concerned. This variable is not set
		in the standard installation.
MOPAC93EXE	This should be set to the name of the Mopac93 executable
		for the machines concerned. This variable is not set
		in the standard installation.
MOPACCONV	This should be set to the name of the executable of
		the mopacconv formatting program, if it is required
		for you configuration of Mopac and Cerius2. See Note 4,
		below.

3. File Names.
--------------

Within each different version of Mopac, the ports for different
machines vary somewhat in their file opening and naming conventions.
For example the SGI version of Mopac6 opens most of the files with
their correct names whereas the IBM version opens them just on the
Fortran units, and relies on the run script to name them properly.

Mopac7 does not appear to name them at all, but Mopac93 opens them
all with their correct names.

For use with Cerius2, we must have a consistent set of file names,
so that the program can read and interpret the output files. We
have decided to adopt the naming convention specified in the 
Mopac93 Manual, Table 14.3. For Mopac6 and Mopac7, all files will
be named according to this convention, by renaming them as necessary
in the run-script.

These names are as follows:

	Channel	Name		Input?	Output?	Contents
	2	name.dat	yes		data-set
	4	name.end	yes		shut command
	5	SCRATCH				internal working
	6	name.out		yes	results
	9	name.res	yes	yes	restart
	10	name.den	yes	yes	density
	11	name.log		yes	log file
	12	name.arc		yes	archive
	13	name.gpt		yes	graphics
	14	user-defined	yes		new paramters
	15	name.esr		yes	esp restart
	16	name.syb		yes	sybyl
	18	name.brz		yes	Brillouin Zone
	20	name.ump		yes	data for grid
	21	name.esp		yes	esp data
	22	SCRATCH				used by GEOUTG

In addition to these, a file 'name.run' is created by Cerius2 which
contains a script to run the complete job. 

4. Binary Graphics File
-----------------------

Mopac produces its graphics data output in a binary file. In most cases
this file will be readable by Cerius2, but there are some circumstances
in which it will not be. For these circumstances, we provide the 
Fortran source code of a small conversion program which will convert
the .gpt binary file into a .fgpt formatted file which will be read.
If the variable MOPACCONV is present in the applcomm.db file for the
machine on which you are about to run Mopac, then the formatter
program will automatically be called, and Cerius2 will read the
results from the formatted file rather than the binary file.

Examples where the conversion program is needed fall into two 
categories:
When Mopac is being run on a machine whose binary data file format is
different from that on the machine on which you are running Cerius2,
e.g. Mopac run on a Cray (64-bit), and Cerius2 being run on a 32-bit
workstation, such as Silcion Graphics.
When Mopac is being run on the same machine as Cerius2, but incompatible
compilation options have been used. For example on the DEC Alpha, using
OSF/1 operating system, it is possible to have binary file written
out different ways according to compilation flags. Cerius2 has used
the flag '-convert big_endian' which forces binary data to be written
in a form compatable with files from SGI, HP and IBM. If your copy
of Mopac was compiled without this flag, then the binary files
produced will not be compatable with Cerius2, and you will need to 
use the conversion utility.

5. Mopac6
---------

As a convenience to our customers, we provide a copy of the Mopac6
executable. For SGI and IBM platforms, this is as was supplied by
QCPE, with no changes. For the HP and DEC platforms, the copy was
generated from the IBM version, with only those changes necessary
for correct running on that particular host.

