Highlights

Erbahar, D., Susi, T., et al., Spectromicroscopy of C60 and azafullerene C59N: Identifying surface absorbed water, Sci. Rep. 6: 35605 (2016). doi: 10.1038/srep35605

Susi, T., et al.Calculation of the graphene C 1s core level binding energy, Phys. Rev. B 91, 081401(R) (2015). doi:10.1103/PhysRevB.91.081401

Susi T., et al.Core level binding energies of functionalized and defective graphene, Beilstein J. Nanotechnol. 5, 121-132 (2014). doi:10.3762/bjnano.5.12

Density functional theory

Density functional theory (DFT) is one of the most powerful tools for simulating the properties of materials. Besides accurately predicting properties such as the electronic and phonon band structures, DFT can be used to understand measurement techniques such as x-ray photoemission spectroscopy.

To simulate core level spectra, we can introduce a core hole on one of the atoms. The hole gets screened very efficiently in a metallic system such as graphene, resulting in an oscillating electron density difference compared to the ground state. The energy difference between the excited and ground states is an estimate of the core level binding energy.

To simulate core level spectra, we can introduce a core hole on one of the atoms. The hole gets screened very efficiently in a metallic system such as graphene, resulting in an oscillating electron density difference compared to the ground state. The energy difference between the excited and ground states is an estimate of the core level binding energy.