Explicit generation of chemical diagrams

LISA is developing, in collaboration with the NCAR (Boulder, Colorado), a system of auto generation of chemical diagrams (GECKO-A) for writing explicitly multiphasic oxidation of VOCs in the atmosphere.


GECKO-A project to (Figure 1) :

- Auto generate explicit chemical schemes for oxidation of a precursor compound in the gas and condensed phases (i.e. provide the list of elementary reactions and associated kinetic constants)

- describe the transfer phase of each organic species (i.e. inform the mass transfer and provide the associated properties: vapor pressure, Henry’s constant, and paraglidingcoefficients).


Figure 1 development of the generator of explicit chemical schemas for multiphase oxidation of organic compounds

This system allows any data and/or new parameterization from studies of laboratory (kinetic constants, product yields of reactions) and estimate the kinetic, mechanistic and thermodynamic missing data based on empirical relationships of type structure/reactivity (Figure 2). The interest of this system is to remove constraints on manual transcription of chemical patterns, allowing the development of really explicit schemes. For example, the application of the GECKO-A to describe the gas compound oxidation such as octane leads to a chemical diagram containing more than one million species.


Figure 2: Operation of the generator of explicit chemical diagrams

In its current version, GECKO-A allows to generate gaseous oxidation schemes of the main families of VOCs emitted into the atmosphere and the transfer of gas/particle mass and gas/clouds of organic species.