  Exoplanet and brown dwarf atmospheres commonly show signs of disequilibrium
chemistry. In the James Webb Space Telescope era high resolution spectra of
directly imaged exoplanets will allow the characterization of their atmospheres
in more detail, and allow systematic tests for the presence of chemical species
that deviate from thermochemical equilibrium in these atmospheres. Constraining
the presence of disequilibrium chemistry in these atmospheres as a function of
parameters such as their effective temperature and surface gravity will allow
us to place better constrains in the physics governing these atmospheres. This
paper is part of a series of works presenting the Sonora grid of atmosphere
models (Marley et al 2021, Morley et al in prep.). In this paper we present a
grid of cloud-free, solar metallicity atmospheres for brown dwarfs and wide
separation giant planets with key molecular species such as CH4, H2O, CO and
NH3 in disequilibrium. Our grid covers atmospheres with Teff~[500 K,1300 K],
logg~[3.0,5.5] (cgs) and an eddy diffusion parameter of logKzz=2, 4 and 7
(cgs). We study the effect of different parameters within the grid on the
temperature and composition profiles of our atmospheres. We discuss their
effect on the near-infrared colors of our model atmospheres and the
detectability of CH4, H2O, CO and NH3 using the JWST. We compare our models
against existing MKO and Spitzer observations of brown dwarfs and verify the
importance of disequilibrium chemistry for T dwarf atmospheres. Finally, we
discuss how our models can help constrain the vertical structure and chemical
composition of these atmospheres.
