In a DRC calculation n.nnn kcal/mol of excess kinetic energy is
added to the system. At the start of a DRC calculation, the atoms are
initially at rest. So kinetic energy cannot be added to the system. When
KINETIC=n.nn is used, the DRC is first run for a few steps until the atoms have
a significant velocity. This is when the kinetic energy amounts to 0.2
kcal/mol. When that happens, the kinetic energy is increased suddenly by
n.nn kcal/mol. The next few steps will show errors in the output as the
energy is added to the system. The use of 0.2 kcal/mol is arbitrary - any small
number could be used.
If a system starts off with an energy of -100 kcal/mol, and KINETIC=10 is used, the DRC will be run with a total (kinetic plus potential) of -90 kcal/mol.
See VELOCITY and Dynamic and Intrinsic Reaction Coordinates for more details.