“…Interestingly, the electronic structure (e.g., the orbital occupation) can dramatically change with U. Once the CoPc molecules are deposited on surfaces, the majority of theoretical studies are based on various flavors of DFT and DFT + U calculations (see for example, references [8,12,[25][26][27][28]. We note, however, that DFT + U is often used without necessarily discussing the impact of correlations on the electronic structure of the free molecule within the very same setup.…”