Shooting from a Saddle

Once one reactive trajectory has been found, one may want to determine more precisely the position of the transition state region. A standard way to do this is to select some points along the trajectory, and, by shooting with random velocities a new MD from this point, measure the probability to reach the surrounding basins of attraction [124]. The different basins of attraction can be identified by different values of a selected set of CV. One can say that the trajectory has fallen in one of the known basins when all the actual CV values satisfy the values characterizing that basin, within a certain tolerance. Given a set of coordinates, one can start a CPMD run where this check is iterated as many times as you like, in order to establish the committor distribution. The search for the saddle point region is initialized when in the section &ATOMS of the input http, the keyword $SADDLE$ $POINT$ is found. In what follows, a subsection for the description of the selected CV is required. It has the same format as the one used for the MTD run.