IRCCAR

The IRCCAR file defines a discretized transformation path. Usually this is taken from an intrinsic reaction coordinate (IRC - using IBRION=40), projected onto a small set of internal coordinates. It is required to define the path-based coordinates IS and IZ in ICONST.

However, this IRC is followed during a biased molecular dynamics (MD) simulation, similar to the Blue moon ensemble method. The Structure of the file is:

N
 a1 b1
 a2 b2 
 a3 b3
 ...
 aN bN

where N is the number of points in the file, a_i is the first basis???, b_i is the second basis.

There is a guide on how to use this tag in the How-to ADD LINK.