The interplay between structure and orbitals in the chemical bonding of graphite

► The electronic structure of graphite is calculated ab initio. We perform these calculations for different values of the lattice parameters, according to their evolution after light excitation reported by ultrafast electron diffraction. ► The changes in the electron energy loss spectrum of graphite due to the above-mentioned structural motions is simulated. ► These simulations are compared to the dynamical EELS spectrum experimentally measured in transmission through a graphite thin film. ► We show that the photoinduced structural motions modulate the electronic structure and give rise to the changes in the EELS spectra recently reported. ► This knowledge is used to simulate the effects of structural motions on the optical absorption spectra and we find that some long-term dynamics of the transient absorption signal are also due to photoinduced structural motions. ► We show how the charge density redistributes in the solid upon light excitation.