RENORMALIZATION-GROUP APPROACH TO SIMPLE REACTION-DIFFUSION PHENOMENA

A field-theoretical model describing simple one-species reaction-diffu sion systems [A + A --> O (inert) or A + A --> A] with an external sou rce is analyzed from a renormalization-group point of view. It is show n that when the dimension of the system is larger than the upper criti cal dimension d(u) = 2, the behavior of the system is governed by a tr ivial fixed point dominated by diffusion. Below the upper critical dim ension, a line of fixed points governs the behavior. Reaction and diff usion processes play an equally important role resulting in a so-calle d anomalous kinetic behavior. This approach confirms previous scaling arguments. Possible generalizations to more complicated models are dis cussed.