Previously we had shown that optimization of coadsorbed BMP-TFSI and Li on graphite (0001) leads to breaking of the N -S bond in TFSI, and that this process is strongly exothermic if three Li atoms are present, while it would be endothermic or less exothermic for one or two Li atoms. Interaction of Li with bulk BMP-TFSI was found to result in a spontaneous reaction of TFSI with Li in a non-activated process, forming different reaction products such as LiNSO2CF3 etc. Here N -S bond breaking was found to be about equally exothermic as S -C of C -F bond breaking. These initial reaction products can decompose further via a sequence of activated steps. In the end, this was found to result in inorganic compounds composed of Li and the elements of TFSI such as LiF, Li2O, Li2S, LiCN or LiCO3 as the most stable reaction products, where the exact contributions depend on the chemical potential of Li, i.e., on the amount of Li available. At not too high chemical potentials, also LiCO3 and in particular LiCN were stable. In contrast, reaction with BMP was found to be less facile. These results closely resemble previous findings in an DFT-MD study on the interaction of a TFSI containing IL, N-butyl-N-methylpyrrolidinium (Pyr14)-TFSI, which at high excess of Li showed complete decomposition of the TFSI anions. In the present study, we want to elucidate the influence of the graphite (0001) substrate. We first calculated adsorption structures and core level binding energies (BEs) of an adsorbed monolayer of BMP-TFSI on graphite (0001) and of adsorbed BMP-TFSI (in the same unit cell) coadsorbed with 1 or 3 Li species, where the latter can be considered as initial state after Li deposition on the BMP-TFSI monolayer covered graphite (0001) surface (see Table , 1 st to 3 rd column). Comparison of the calculated BEs with experimental ones shows the following trends: Post-deposition of Li was shown in Figure to lead to an up-shift of the experimental core level signals by about 1 eV, which agrees generally well with the trends in the calculated BEs. Exceptions are the F1s peak, where the shift is generally slightly smaller, both in experiment and calculated, and the S 2p peak, where in two of the calculated structures the shift is very small or even negative. This latter result is consistent with experimental findings, when considering also the lower BE peak fitted into the doublet at about 170 eV. Hence, the up-shift of the peaks in the spectra recorded upon Li post-deposition can be assigned to chemical effects resulting from coadsorption of Li with BMP-TFSI as shown in Table or to the formation of initial reaction products with a largely intact molecular structure. Comparison of these results with those reported recently for reaction between thick BMP-TFSI multilayers and Li shows rather similar trends, with the exception that the up-shift upon Li postdeposition is smaller in that case than for the adsorbed BMP-TFSI monolayer. This can be reconciled by the fact that due to the vacuum level pinning in the multilayer system its BEs were already up-shifted compared to the monolayer. Hence, in that case the BEs are less affected by initial interaction with Li, as long as the molecular structure of the ion pairs is largely intact.