In collision theory, the Lindemann's assumption was originally taken as that each collision would totally transfer the energy to facilitate the reaction to happen, it was also cited as the "strong collision" assumption. However, in many cases the possess energy may not be strong enough and the "weak collisions" may happen, as described in the research on the isotope effect in ozone formation, by Gao and Marcus (Science 2001, 293, 259-263).