  We analyze the properties of electron-phonon couplings in K3Picene by
exploiting a molecular orbital representation derived in the maximally
localized Wannier function formalism. This allows us to go beyond the analysis
done in Phys. Rev. Lett. 107, 137006 (2011), and separate not only the intra-
and intermolecular phonon contributions but also the local and non-local
electronic states in the electron-phonon matrix elements. Despite the molecular
nature of the crystal, we find that the purely molecular contributions
(Holstein-like couplings where the local deformation potential is coupled to
intramolecular phonons) account for only 20% of the total electron-phonon
interaction lambda. In particular, the Holstein-like contributions to lambda in
K3Picene are four times smaller than those computed for an isolated neutral
molecule, as they are strongly screened by the metallic bands of the doped
crystal. Our findings invalidate the use of molecular electron-phonon
calculations to estimate the total electron-phonon coupling in metallic picene,
and possibly in other doped metallic molecular crystals. The major contribution
(80%) to lambda in K3Picene comes from non-local couplings due to phonon
modulated hoppings. We show that the crystal geometry together with the
molecular picene structure leads to a strong 1D spatial anisotropy of the
non-local couplings. Finally, based on the parameters derived from our density
functional theory calculations, we propose a lattice modelization of the
electron-phonon couplings in K3Picene which gives 90% of ab-initio lambda.
