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
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
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
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
Last, Opt'n Path also came from the name of a wonderful arcade game:
Goblins. You can try it for free
Some information about this program
Here are some files describing was CARTE was, and thus more or less
what Opt'n Path is:
CarteDay.pdf PDF presentation of what is CARTE, and also what CARTE is not.