  In this article, we propose a generalized non-equilibrium chemical kinetics
model from \textit{ab initio} simulation data obtained using accurate potential
energy surfaces developed recently for the purpose of studying high-temperature
air chemistry. First, we present a simple cross-section model for dissociation
that captures recent \textit{ab initio} data accurately. The cross-section
model is analytically integrated over Boltzmann distributions and general
non-Boltzmann distributions to derive general non-equilibrium dissociation
model. The general non-Boltzmann model systematically incorporates key physics
such as dependence on translational energy, rotational energy, vibrational
energy, internal energy, centrifugal barrier and non-Boltzmann effects such as
overpopulation and depletion of high energy states. The model is shown to
reproduce the rates from QCT for Boltzmann distributions of internal energy
states. Reduced rates in non-equilibrium steady state due to depletion of high
internal energy states are also predicted well by the model. Furthermore, the
model predicts the enhanced rates as observed due to significant overpopulation
of high vibrational states relative to Boltzmann distributions while the gas is
in non-equilibrium in the transient phase. The model provides a computationally
inexpensive way of incorporating non-equilibrium chemistry without incurring
additional cost in the existing computational tools. Further comparisons of the
model are carried out in another article, where simplifications to the model
are proposed based on the results.
