KIMYA is a new code for solving the system of differential equations
describing the temporal behaviour of a chemical network. This paper
presents a simple and easy to implement numerical method and tests of its
accuracy.
KIMYA was designed for incorporating a chemical network into
multi-dimensional gasdynamical simulations. In order to test our code we
compute three numerical simulations: a model of the chemical evolution of
a dark cloud (which we compare with previous calculations), and a model
of of nitric oxide formation during a lightning discharge simulated with a
laser pulse. The latter is done both with a single parcel calculation, as
well as a fully hydrodynamical/chemical model, which we compare with
results from a laboratory experiment.