# Can the relative velocity of two colliding molecules be too large to allow reaction to occur?

In a collision between two molecules, can the relative velocity of one with respect to the other be too large for a reaction to occur? For example, suppose that two molecules collide with (a) a perfect orientation to enable a reaction and (b) kinetic energy in excess of the activation energy, but their relative velocity is very large in magnitude. Will the two molecules simply bounce and part ways chemically unchanged?

• If molecules are colliding with good orientation and a little more than the activation energy, they will react. Aug 16, 2022 at 19:07
• ... but it may happen, if they cannot release the the reaction energy by other way, they revert the reaction back. Like 2H <=> H2* -> H2 + energy Aug 16, 2022 at 19:13
• @Poutnik - did you mean the last $H2$ to be $2H$? Aug 16, 2022 at 19:40
• @JonCuster No, I did not. If H2* is not able to pass the energy, the bond breaks. If it is, H2 stays. Notice the first arrow is bidirectional. Aug 16, 2022 at 22:56
• Too high kinetic energy may lead to alternative, destructive reactions. O may react with O2 to form O3, but can with enough energy also form 3 O instead. Aug 17, 2022 at 11:46