The importance of an accurate CH4 vibrational partition function in full dimensionality calculations of the H+CH4→H2+CH3 reaction

The vibrational energies of methane in Jordan-Gilbert surface were calculated using the multimode code. This code uses an n-mode representation of the potential and the variational procedure to obtain accurate vibrational energies. These energies were later on used to calculate the accurate vibrational partition function for methane to correct the rate constant. The energies of low lying vibrational states were converged to within 1 cm-1 for three mode representation of the potential.