Partition Functions, A-Factor, Activation Energy

We come to the final computations. The input parameters to this module summarize what has been found by the previous two: The coordinates of the TS on the PES and its (real) vibrational modes. This allows now to determine the translational, rotational and vibrational partition functions for all particles. The ingredients to all this are the diatomic constants D_e, R_e, b, and w_e for H₂ and HBr. The rest belongs to the folklore of the Leps model and Eyring's TST. Finally, giving the temperature for which we want the rate constant (the frame 'StiffHBr' under 'Chemical Kinetics' shows a mechanism, where we need this constant at 363.2 K), we obtain the A-factor (preexponential factor) and, from the difference of the TS-energy and the groundstate of the H₂ molecule (incl. their zero-point energies), the exponential factor as well as the activation energy. This is summarized in the next frame.