A collision is described as successful or effective if the particles:
Collide with the right amount of energy. This is why, generally increasing the temperature of a reaction leads to an increased number of successful collisions. Higher temperature means a higher average kinetic energy. It is this minimum energy requirement (sometimes called activation energy) that must be met to achieve a successful collision
Collide in the correct orientation. Meeting the minimum energy requirement is not enough, particles must also collide in the correct orientation.
