Non-linear field dynamics of reacting nuclear, atomic and molecular species

We develop a field theoretical formalism for describing the non-linear dyna mics of interacting nuclear, atomic and molecular species. Specifically, fo ur simple types of reaction are considered all of which involve up to two r eactants and two products. The equations of motion for space- and time-depe ndent quantum order parameter fields, describing the distribution of reacta nt and product species, are derived from Heisenberg's equation using approp riate second-quantised Hamiltonians. For simplicity, both internal degrees of freedom and heat bath modes are being neglected at this stage. We solve a number of cases exactly both in the space-independent and space-dependent regimes. The results obtained possess a variety of interesting properties which include solitonic behaviour and propagating waves of various types in dicating the existence of a wealth of non-linear phenomena. (C) 2001 Elsevi er Science B.V. All rights reserved.