<Li> For order two, the rate constant has units of L mol s (or M s) </Li> <Li> And for order three, the rate constant has units of L mol s (or M s) </Li> <P> Calculation of rate constants of the processes of generation and relaxation of electronically and vibrationally excited particles are of significant importance . It is used, for example, in the computer simulation of processes in plasma chemistry or microelectronics . First - principle based models should be used for such calculation . It can be done with the help of computer simulation software . </P> <P> Rate constant can be calculated for elementary reactions by molecular dynamics simulations . One possible approach is to calculate the mean residence time of the molecule in the reactant state . Although this is feasible for small systems with short residence times, this approach is not widely applicable as reactions are often rare events on molecular scale . One simple approach to overcome this problem is Divided Saddle Theory . Such other methods as the Benett Chandler procedure, and Milestoning are also developed for rate constant calculations . </P>

Rate constant units for a second order reaction