1,127 research outputs found
On the Static Dielectric Permittivity for Coulomb System in the Long Wavelength Limit
On the basis of the exact relations the general formula for the static
dielectric permittivity for Coulomb system is found in the region of small wave
vectors. The obtained formula describes the dielectric function of the Coulomb
system in both limits: in the "metallic" state and in the "dielectric" one. On
this basis the determinations of the "apparent" dielectric and the "apparent"
radius of screening are introduced. In the random phase approximation (RPA) the
exact relations for the function dielectric function of the electron gas in the
long-wavelength region of the wave vectors are found for an arbitrary
degeneration of the particles.Comment: 5 pages, no figure
True Dielectric and Ideal Conductor in Theory of the Dielectric Function for Coulomb System
On the basis of the exact relations the general formula for the static
dielectric permittivity e(q,0) for Coulomb system is found in the region of
small wave vectors q. The obtained formuladescribes the dielectric function
e(q,0) of the Coulomb system in both states in the "metallic" state and in the
"dielectric" one. The parameter which determines possible states of the Coulomb
system - from the "true" dielectric till the "ideal" conductor is found. The
exact relation for the pair correlation function for two-component system of
electrons and nuclei g_ei(r) is found for the arbitrary thermodynamic
parameters.Comment: 5 pages, no figure
Kramers-Kronig Relations For The Dielectric Function And The Static Conductivity Of Coulomb Systems
The mutual influence of singularities of the dielectric permittivity e(q,w)
in a Coulomb system in two limiting cases w tends to zero, q tends to zero, and
opposite q tends to zero, w tends to zero is established. It is shown that the
dielectric permittivity e(q,w) satisfies the Kramers-Kronig relations, which
possesses the singularity due to a finite value of the static conductivity.
This singularity is associated with the long "tails" of the time correlation
functions.Comment: 9 pages, 0 figure
- …