In this entry I'd like to document something that I get asked by few people and for which I assembled a script several years ago. I'd like to put it here for everyone to use (and perhaps for some to contribute, just a wish). In the past I've worked on something called "Path Collective Variables" (PCVs) which are some useful descriptors that are used in enhanced sampling (umbrella sampling, metadynamics, steered-MD and others). The essence of the PCVs is that if you have a trajectory, being it true or fictitious, of a reactive event you can use this as a blueprint, a sort of "track" and ask the system to walk over it using some enhanced sampling method so that you will be able to measure the thermodynamic force along it and calculate the free energy. Getting a rough reactive trajectory can be simple in many cases. One can put a harmonic restraint on the coordinate of your target (say "state B") structure and pull the system toward it wi...
Bignose's box of stuff
Just a box where I can collect things that I care about