Dear All, Recently I bumped into some problem with my MESMER calculations. After some time the total isomer population are decreasing, reaching 0. Previously I have encounterd this problem in other systems, where I have tested each elementary reaction step to see in which the problem occurs. Usually it occured in the reactionsteps with the low barriers (10-20 kJ/mol or less), which I could just overestimate by increasing the size of the barrier or just simply exclude it. Although in my new system...