For a reaction to occur, we assume that two particles collide, have sufficient energy to react, and are oriented appropriately....or so I've read. The first one is straight forward. The second two I have questions about. For convenience, let's say A + B-> AB is what we're looking at. This reaction could have a recorded activation energy, presumably something determined experimentally at thermal equilibrium. Since both particles have a velocity distribution, a certain fraction of collisions will have sufficient energy to react. However, what if we think of A* + B -> AB? We have a bit of extra energy so I'm guessing we'd need a third body or we'd see a temperature increase, but let's ignore that. Is the activation energy still valid? I realize that the Ea tabulated is for an energy distribution that accounts for a certain fraction of A*, but let's say we have an overabundance of A* particles that are still at thermal equilibrium. Does a unit of energy in the form of electrical potential equal that "pound for pound" with that of heat/velocity? Is there any theory/method to figure out an appropriate Ea for the second process? In regards to the orientation, I assume this has something to do with the proper orbitals overlapping (can you tell I'm not a chemist yet?). So this last criterion is something that would always average out into the value of Ea if everything is isotropic, no? So in a weak electric field, this would change a bit even if no excited states were being generated? Also, does the influence of A and B on each other with no external field cause the particles/molecules to reorient themselves to encourage/discourage the reaction? Or is it just a strict probability of the molecules being at the right orientation when they collide? Thank you for any help. I hope I posted this in an ok location.