Date of Award
Doctor of Philosophy (PhD)
The generalization of the zero temperature local density functional theory of inhomogeneous electron systems to finite temperature ensembles is discussed. A local exchange-correlation potential, V(,xc), needed for a finite temperature Kohn-Sham scheme, is developed based on the investigation of first-order exchange and 'ring'-diagram contribution to correlation effects for a wide range of electron densities and temperature. Comparison is made with existing results in the fully degenerate and non-degenerate limits. In the intermediate degeneracy region, the correlation effect is found to be enhanced--the importance of this for various physical systems is pointed out. An application of V(,xc) is made to illustrate the effect on Kohn-Sham eigenvalues for a neon impurity embedded in a dense, laser plasma, and compared with corresponding self-consistent Hartree results. A fully self-consistent calculation of Perrot using our V(,xc) for a proton in a electron gas is also discussed. A connection is made between the finite temperature Kohn-Sham effective potential with the temperature dependent Lindhard screened potential. This gives a scheme to investigate the electron screening effects in the intermediate degeneracy region and interpolates between the well-known Thomas-Fermi screening in the degenerate limit and Debye-screening in the classical limit. Applications are made to study the screened energy levels for charged impurities in dense, hot laser plasmas and in highly doped semiconductors. An estimate of Mott transition is also obtained. Results are compared with other screening models. The significance for plasma diagnostics of the striking differences obtained in the results is pointed out.
Gupta, Uday, "Density Functional Formalism: I. Finite Temperature Theory. II. An 'Atom' in a Hot, Dense Plasma." (1981). LSU Historical Dissertations and Theses. 3685.