Relaxed structure containing the muon (shown in Fig. S16(a)) can be found in 'Nb_muon.cif'. Here the muon is represented by a 
hydrogen atom.

Displacements of the Nb ions as a function of distance from the muon site (shown in Fig. S16(b)) can be found in 'displacements_Nb.dat'.
First column is distance of the ion from the muon site, second column is radial displacement. Both are measured in angstroms.

Density of states for the two Nb atoms within the conventional unit cell can be found in Nb.dos.dat. The first column gives the energy 
(relative to the Fermi energy) and the subsequent columns give the density of states for each of two Nb atoms.

The corresponding density of states obtained when including the muon (Fig. S16(d)) can be found in Nb_mu.dat. Columns 2-5 contain the DOS
for the four Nb atoms forming the coordination tetrahedron of the muon and column 6 contains the muon DOS.