, OH, and CH*

High-level gas-phase electronic structure analysis are indispensable for gaining useful insight on the chemical and physical processes that occur in gas plasmas. However, the plasma models and the predictions are highly dependent on the input data. Hence the utilization of ab initio tools for data generation and property prediction is preferred. In the present work, we have performed highly accurate theoretical analysis for H₂, CH, OH and their ions. Specifically, using multireference methods we have studied the reactions of ground and excited atomic or ionic fragments to investigate their formation. We analysed their full potential energy profiles and report a series of energy related properties and radiative properties. Furthermore, we are interested in extending our approaches to other diatomic molecules of relevance to the GEC community.