  Following to the recently published approach [Phys. Rev. Lett. 119, 073901
(2017); New J. Phys., 123014 (2017)], we refine and accomplish the general
scheme for the unified description of the momentum and angular momentum in
complex media. The equations for the canonical (orbital) and spin linear
momenta, orbital and spin angular momenta in a lossless inhomogeneous
dispersive medium are presented in the compact form analogous to the
Brillouin's relation for the energy. The results are applied to the surface
plasmon-polariton (SPP) field, and the microscopic calculations support the
phenomenological expectations. The refined general scheme correctly describes
the unusual SPP properties (transverse spin, magnetization momentum) and
additionally predicts the singular momentum contribution sharply localized at
the metal-dielectric interface, which is confirmed by the microscopic analysis.
The results can be useful in optical systems employing the structured light,
especially for microoptics, plasmophotonics, optical sorting and
micromanipulation.
