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Master Equation Solver for Multi Energy well Reactions

MESMER (Master Equation Solver for Multi Energy well Reactions) is an open source programme designed to solve the chemical master equation for a reaction in order to theoretically predict rate coefficients for both gas phase and solution phase systems. MESMER is an efficient, user friendly tool for complementing and interpreting experimental observations and for estimating rate coefficient for reactions, in the case where experiments are yet to be performed. Unlike conventional transition state calculations, the master equation approach makes no assumptions about the species involved in the reaction being at equilibrium. Given a potential energy surface for a reaction involving an arbitrary number of intermediates, such as those shown in the accompanying figure, master equation calculations can consider the coupling between reactive and energy transfer processes in order to obtain a phenomenological picture of the system.


For new users a web based GUI (Graphical user interface) has been developed by Dr Xiaoqing You and her group. This can be found at the following address:


MESMER may be freely downloaded using the following link:

Information about the functionality of MESMER and a number of example systems studied can be accessed via the tabs. More detailed information can be accessed via the manual though the link above or through the recent MESMER publication below:

MESMER website maintained by Dr Robin Shannon (

Schematic potential energy surface for a typical MESMER application.

Temperature dependence of the O2 + CH2COCH3 reaction with MESMER fits to the experimental data. Here the theoretical model has been extensively optimised to fit the experimental data