Numerical modeling of nonequilibrium state-to-state carbon dioxide kinetics is a computationally complex problem requiring the solution of a huge system of stiff differential equations. In the present study, we use parallel numerical scheme, based on the extended backward differential formula with adaptive timestep strategy. Using this scheme, we study the contribution of various types of energy exchanges to the solution of kinetics equations. The comparison of the results obtained with the use of the "cut" and full state-to-state approaches is also shown in the paper.