It is often of interest to calculate the relative translational energy release in a given reaction, as this can be compared to experimental values determined from e.g. mass spectrometry [12] . Although this quantity is printed in the output from DALTON in the entire dynamical walk, the relative translational energy release should be calculated, due to basis set superposition errors and vibrational and rotational excitation in the departing molecular fragments, in the way described here.
The geometry of the last iterations for which relative translational
energy release is known, is used as a starting point for minimizing
the two molecular fragments as described in
Section 
. As a check of this minimization one
might also minimize the two molecular fragments separately, and check
this total energy against the energy obtained when minimizing the
molecular supersystem. The energies should be almost identical, but
small differences due to basis set superposition errors may be
noticeable.
The barrier height can then be calculated by subtracting the energy of the molecule at the transition state and the energy for the separated molecular fragments, or an experimentally determined barrier height may be used. The relative translational energy release may then be obtained by dividing the translational energy release from the last DALTON iteration by the barrier height. This number will not be identical to the number printed in the DALTON -output, because of the different vibrational and rotational state of the molecule in the final iteration point as compared to the minimized structure.