Suppose we are doing heterogeneous catalysis, for example, between nitrogen and hydrogen to create ammonia in the presence of a solid catalyst, like rhuthenium. It's obvious that the gas molecules don't "collide" directly and, therefore, the Arrhenius equation does not completely apply. Does a modified version of the equation exist that takes this into account?
My guess would be that since catalysts generally decrease the activation energy of a reaction, the activation energy value would possibly have a fractional component to it. Furthermore, because the reaction is occurring on a surface, the decreased direct collisions may affect the rate. I would greatly appreciate it if someone could point me in the right direction.