Three-dimensional tomographic imaging of molecular orbitals by photoelectron momentum microscopy Martin Graus, Christian Metzger, Manuel Grimm, Pascal Nigge, Vitaliy Feyer, Achim Schöll and Friedrich Reinert Eur. Phys. J. B, 92 4 (2019) 80 Published online: 10 April 2019 DOI: 10.1140/epjb/e2019-100015-x