Importantly, these two functionals displayed higher errors for predicting ΔET-Q hence they might not be ideal for predicting excited-state properties. We further studied the interaction of a CO molecule with a Hf surface with BP86, BLYP, PBE, B3LYP, and PBE0 functionals and observed that the GGAs consistently predicted smaller chemisorption energies (by ~8 kcal/mol) compared to their gas-phase Des but the global hybrids yielded more consistent results. Taken together with our analysis of benchmarks on the molecular systems, this encourages us to suggest B3LYP as a promising functional for both molecular and solid-state models of Hf-C interactions.