A multiquantum integral equation for the longitudinal dielectric function is derived accounting for of pair correlations. The Heisenberg equation of motion and fluctuation-dissipation theorem has been used to calculate a microscopic polarization. It has been shown that a kinetic equation for a polarization may be represented as a power series in fluctuations of instantaneous field near the mean field. Direct Coulomb pair correlations have been evaluated explicitly by means of a fluctuation-dissipation theorem. The energy and the effective mass of an electron of momentum k in the degenerate electron system and damping of one-electron states have been computed at r(s) >= 1.
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