Abstract: The collisions among atoms, ions, and molecules are fundamental processes in the universe. These collisions occur through various elastic and inelastic processes which include the excitation of partners (electronic, vibrational, rotational excitations), charge transfer through the exchange of electrons, and reactions that result in the formation of new species. These processes affect the absorbing and emitting spectral lines of atoms, ions, and molecules, thus playing a significant role in the analysis of stellar spectra of the astrophysical environment. A thorough understanding of these processes and the ability to perform accurate calculations are vital for achieving accurate measurements of stellar properties, particularly abundances. The detailed calculations of these inelastic collision processes involve intricate atomic or molecular structure calculations to generate wave functions and potential energies needed for performing effective dynamics calculations. These calculations are very complex and difficult to proceed with. Often, these inelastic processes occur through non-adiabatic interactions, which results in the breakdown of the Born-Oppenheimer approximation. In such cases, the dynamics evolve on coupled potential energy surfaces, imposing theoretically and computationally challenging tasks. Here, in this project we will use quantum chemistry software MOLPRO to carry out the electronic structure calculations. Further, we will perform quantum scattering calculations for the dynamics study to get the cross-sections and rates of the collision processes, which will be applied to model the astrophysical spectra.