The first example is the deprotonated formic acid trimer which was thoroughly analysed via infrared action spectroscopy in helium nanodroplets by Taccone et al. Three conformers of interest were identified (see Fig. ). One finds a mismatch between the prevalent structure observed in experiment and the computed global minimum. The potential reasons for this mismatch include the harmonically computed zero-point vibrational energy, as well as potential shortcomings of the experiment, namely kinetics and dynamics of the cluster formation and solvent e↵ects. In the closely related proton-bound formate dimer system, constrained NEO molecular dynamics have already demonstrated the usefulness of multicomponent calculations in such strongly-bound hydrogenbond systems. In Fig. we show the resulting energetic orderings of the three lowest isomers obtained with Born-Oppenheimer based harmonically corrected B3LYP-D3(BJ), anharmonically corrected via vibrational perturbation theory (VPT2) and finally multicomponent NEO-B3LYP-D3(BJ). The harmonic B3LYP-D3(BJ) results are in agreement with the ordering reported by Taccone et al. One should note that in their study not only density functional based but also wave function methods, MP2 and CCSD(T), as well as double-hybrid approaches result in the same energetic ordering. The latter is in disagreement with both VPT2 and NEO results. Instead of isomer 1, isomer 2 becomes the global minimum by 1.07 and 0.93 kJ mol 1 for VPT2 and NEO, respectively. These are in agreement with the experimental exclusive observation of isomer 2.