Reaction path construction and determination

Computational chemistry has now become a standard tool to evaluate energy (and free energy) differences along a reaction path. However, when dealing with chemical reactions, one often relies on ab initio programs. This leads in turn to simulation costs much higher than for classical force fields. As a consequence, one must look for ways to i) generate initial path as close as possible to the unknown actual path, and ii) efficient ways to optimize this path. Many methods already exist for the optimization of reaction path such as the Nudged Elastic Band (NEB) method and the String method. In both approaches, the reaction path is discretized as an ensemble of intermediate structures (called images) describing the transformation of the reactants into the products. The originality of our approach is to use different sets of coordinates to describe the system.
This is implemented in a home made program called Opt'n Path.

Some history about this program

I have been working on chemical reactivity and reaction path construction and optimization for many years. After joining the Laboratoire de Chimie at the ENS de Lyon, I started to improve the user interface of my routines. This shortly became a task in the SIRE ANR project under the name CARTE that meant: Chemins Automatisés pour la Réactivité chimique incluant la Température, la pression et l'Environnement. This version was distributed to the persons involved in the SIRE project, but not publicly.
When the SIRE project was completed, I decided to release it publicly under the name OpenPath. However, we soon discovered that this name was already used by many projects so that it is now distributed under the name Opt'n Path.

Why this name ?

On top of being a project name not already used, Opt'n Path was chosen because it describe what our code can do: Optimization and reaction Path.
More, at least to me, Opt'n still sounds a bit like Open, and I like the idea of releasing an Opensource code. On top of it, I hope that this program will help its users to open some new path in their research :).
Last, Opt'n Path also came from the name of a wonderful arcade game: Ghost'n Goblins. You can try it for free here.

Some information about this program

Here are some files describing was CARTE was, and thus more or less what Opt'n Path is:

How to get it ?

As I said, Opt'n Path is realeased as a free and open source software. However, to have an idea of who is using it, you have to be registered to have access to the download section.
Last update: 03/2013 by PFL.