Editing G09 (section)

== MECP calculations (Python version) ==

Jaime Rodríguez-Guerra and Ignacio Funes have adapted the old-FORTRAN script to find Minimum Energy Crossing Points in Gaussian (by Prof. Jeremy Noel Harvey). Now, a little script governs all the process and you do not need to recompile and copy the files when your number of atoms change. In addition, some issues such as the generation of initial input files, the selection of the Gaussian version (g09 or g16), the thresholds, maximum number of steps, have been automatized. 

1.- Download the program from the [https://github.com/jaimergp/easymecp easyMECP's GitHub repository]:

* Go to the [https://raw.githubusercontent.com/jaimergp/easymecp/master/easymecp/easymecp.py following web-page] and download the program. You just need to copy the <code>easymecp.py</code> script to your working directory. The script has many arguments that can be easily specified (Gaussian version, thresholds...), you can find all the information by typing <code>python easymecp.py -h</code>. Remember that if you want to execute python scripts in your kimik2 home directory, you should activate the corresponding module (<code>module load python/3.5.2</code>).

2.- Prepare your input files. It should contain the following:
* <code>Input_header_A</code> and <code>Input_header_B</code>: this represents your upper part of the calculation (up to charge/multiplicity) for each multiplicity.
* <code>geom</code>: this file contains your geometry. You do not need to format it with atomic numbers: if your input has the atomic symbols, now the program works fine!
* <code>footer</code>: contains additional information (normally basis set). 

3. Run the program: you need to load the Python module in the machine, so the submit script should be modified. Here you have examples that you can modify according to the machine you are using. In addition, this script calls directly the program and it should have the corresponding flags to define thresholds, gaussian version. One example for g09 and other for g16 can be download here:
[[Image:Mecpy_pruebas.tgz]]

Also, if you need to restart your calculation, just review your file <code>geom</code> and send the script again, it automatically save your old results in JOBS1, JOBS2... directories. You can find more useful information in the [https://github.com/jaimergp/easymecp#usage GitHub webpage]!