Recent Updates to the Gas-phase Chemical Reactions and Molecular Lines in CLOUDY: Their Effects on Millimeter and Submillimeter Molecular Line Predictions

Here, we present our current updates to the gas-phase chemical reaction rates and molecular lines in the spectral synthesis code cloudy, and its implications in spectroscopic modeling of various astrophysical environments. We include energy levels, and radiative and collisional rates for HF, CF⁺, HC₃N, ArH⁺, HCl, HCN, CN, CH, and CH₂. Simultaneously, we expand our molecular network involving these molecules. For this purpose, we have added 561 new reactions and have updated the existing 165 molecular reaction rates involving these molecules. As a result, cloudy now predicts all the lines arising from these nine molecules. In addition, we also update H₂-H₂ collisional data up to rotational levels J = 31 for v = 0. We demonstrate spectroscopic simulations of these molecules for a few astrophysical environments. Our existing model for globules in the Crab Nebula successfully predicts the observed column density of ArH⁺. Our model predicts a detectable amount of HeH⁺, OH⁺, and CH⁺ for the Crab Nebula. We also model the interstellar medium toward HD185418, W31C, and NGC 253, and our predictions match with most of the observed column densities within the observed error bars. Very often molecular lines trace various physical conditions. Hence, this update will be very supportive for spectroscopic modeling of various astrophysical environments, particularly involving submillimeter and mid-infrared observations using the Atacama Large Millimeter/submillimeter Array and the James Webb Space Telescope, respectively.