This work focuses on the development of a detailed chemical kinetics mechanism for the decomposition of the high energy density compound cubane. Quantum mechanics based ab initio calculations have been carried out to elucidate the various chemical pathways that lead to the formation of previously known product species from cubane. Optimised structures of ground states and transition states appearing in the chemical reaction scheme were obtained by using various levels of theory. Minimum energy paths were also traced for each elementary reaction. The mechanism thus obtained, along with the computed rate parameters and thermodynamic data, was used in a flow reactor model to simulate a flow reactor experiment that was carried out previously by others, Comparison of the simulation and experimental results validated the formulated reaction mechanism and provided valuable insights into the chemical behaviour of cubane. (C) 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.