  NbP is one member of a new class of nodal loop semimetals characterized by
the cooperative effects of spin-orbit coupling (SOC) and a lack of inversion
center. Here transport and spectroscopic properties of NbP are evaluated using
density functional theory methods. SOC together with the lack of inversion
symmetry splits degeneracies, giving rise to "Russian doll nested" Fermi
surfaces containing 4*10$^{-4}$ electron (hole) carriers/f.u. Due to the modest
SOC strength in Nb, the Fermi surfaces map out the Weyl nodal loops. Calculated
structure around T$^*$~100 K in transport properties reproduces well the
observed transport behavior only when SOC is included, attesting to the
precision of the (delicate) calculations and the stoichiometry of the samples.
Low energy collective electron-hole excitations (plasmons) in the 20-60 meV
range result from the nodal loop splitting.
