Chemical organizations in atmospheric photochemistries - A new method to analyze chemical reaction networks

The theory of chemical organizations is proposed as a new method to study atmospheric reaction networks. Here, the method is applied to an atmospheric photochemistry model of Mars. Only considering its stoichiometry, the reaction network is decomposed into self-sustaining sub-networks called organizations. These are arranged into an overlapping hierarchy representing the organizational structure of the reaction network. We analyze both the day- and nightside of Mars, discovering a simple, combinatorial hierarchy of organizations for the nightside and a rich and complex hierarchy for the dayside. One organization representing the recycling pathway for CO2 could be identified. Molecular species of similar molecular structure are found to often appear together in organizations. For the dayside, only few organizations contain many molecular species, indicating that only few steady states featuring a high diversity in molecular composition exist. Using a simulated concentration profile, organizations can be grouped into four categories with distinct intensity profiles. (c) 2006 Elsevier Ltd. All rights reserved.