Correlation balance for describing carbenes: An NOF study

Carbenes are a remarkable type of molecules because the two electrons that might be paired or unpaired, providing singlet triplet state, respectively. The preference for one these states can measured by singlet-triplet energy gap; however, theoretical prediction is challenging when static correlation arises, and an adequate balance with dynamic required to achieve correct predictions. Piris Natural Orbital Functionals (PNOFs) have been used before deal other problems, but they suffered from lack correlation, which has solved coupling PNOF7 many-body perturbation theory. Recently, development Global Functional (GNOF) proposed aim including without need couple theory, thus becoming promising alternative study chemical problems. In this work, we applied PNOF family functionals compute adiabatic gaps set simple carbenes compared them those computed coupled-cluster methods experimental values available. We found GNOF achieves results due intrinsic correlation. regard, presents errors lower than PNOF7, comparable NOF-c-MP2, capable predicting tendency substituent effects, proving suitable further application predict general gaps.