  We present a publicly available library of model atmospheres with
radiative-convective equilibrium Pressure-Temperature ($P$-$T$) profiles fully
consistent with equilibrium chemical abundances, and the corresponding emission
and transmission spectrum with R$\sim$5000 at 0.2 $\mu$m decreasing to
R$\sim$35 at 30 $\mu$m, for 89 hot Jupiter exoplanets, for four re-circulation
factors, six metallicities and six C/O ratios. We find the choice of
condensation process (local/rainout) alters the $P$-$T$ profile and thereby the
spectrum substantially, potentially detectable by JWST. We find H$^-$ opacity
can contribute to form a strong temperature inversion in ultra-hot Jupiters for
C/O ratios $\geq$ 1 and can make transmission spectra features flat in the
optical, alongside altering the entire emission spectra. We highlight how
adopting different model choices such as thermal ionisation, opacities,
line-wing profiles and the methodology of varying the C/O ratio, effects the
$P$-$T$ structure and the spectrum. We show the role of Fe opacity to form
primary/secondary inversion in the atmosphere. We use WASP-17b and WASP-121b as
test cases to demonstrate the effect of grid parameters across their full
range, while highlighting some important findings, concerning the overall
atmospheric structure, chemical transition regimes and their observables.
Finally, we apply this library to the current transmission and emission spectra
observations of WASP-121b, which shows H$_2$O and tentative evidence for VO at
the limb, and H$_2$O emission feature indicative of inversion on the dayside,
with very low energy redistribution, thereby demonstrating the applicability of
library for planning and interpreting observations of transmission and emission
spectrum.
