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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 neutral and ionic diatomic molecule species, namely FeH, CN, AlO, CH, OH, and H₂. Specifically, we used multireference methods to study the reactions of ground and excited atomic or ionic fragments and investigate their molecular formation. We analysed their full potential energy profiles and report a series of their energy related properties and radiative properties.