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On the single‐particle spectrum of an interacting electron gas
Author(s) -
Hedin L.,
Lundqvist B. I.,
Lundqvist S.
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560010688
Subject(s) - electron , physics , atomic physics , plasmon , momentum (technical analysis) , excitation , fermi gas , particle (ecology) , spectrum (functional analysis) , quantum mechanics , oceanography , finance , economics , geology
In the many‐body theory of conduction electrons in a metal the single‐particle spectrum is described not simply by the energy versus momentum relation as in band theory but by a function that describes the actual shape of the spectrum for a given momentum and has an appreciable spread in energy. Calculations of the spectral strength function for electrons in a uniform electron gas are described, where, besides the usual quasi‐particle peak and a broad background, a new peak of appreciable strength appears for small momenta. The new excitation corresponds to a coupled mode of an electron and real plasmons. It has a strong effect on the energy distribution of electrons in the system. The effects should show up only in certain types of experiments that depend on the energy spectrum in the region where the new mode occurs.