Where q i is the donor orbital occupancy, ε i and ε j are the diagonal elements (orbital energies) and F(i,j) is the interaction element between donor and acceptor orbitals and is known as The magnitude of cationanion interaction can be related to the charge transfer component of E (2) n→σ*, E (2) n→ 𝜋* C=C and/or E (2) n→π*, which is proportional to the amount of electron density (qi) donated from the filled donor lone-pair orbital into the empty σ* and/or π* antibonding orbital, moderated by the energy difference between these two fragment orbitals (Δε), and thus the NBO analysis on the DFT optimized structure allows the analysis of intermolecular donor-acceptor orbitals interactions. and analysis of a large range of ionic liquid ion pair conformers, geometric influences and the impact of multiple concomitant hydrogen bonds that need to be better understood.