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Free energy and dispersion forces via response functions
Author(s) -
Obcemea Ceferino H.
Publication year - 1987
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.560310113
Subject(s) - casimir effect , van der waals force , physics , quantum mechanics , london dispersion force , black body radiation , quantum , quantum field theory , dispersion relation , dipole , argument (complex analysis) , classical mechanics , theoretical physics , quantum electrodynamics , radiation , chemistry , molecule , biochemistry
In a recent paper [5], Ford, Lewis, and O'Connell proposed a remarkable formula for the change in the free energy in terms of the susceptibility alone. This formula came out of their treatment of a quantum oscillator interacting (via dipole coupling) with a blackbody radiation field at finite temperature T . As a result, they found a modification to the Planck formula due to finite line width and a positive energy shift which is of quantum electrodynamical origin. I shall show in this paper that the above result is a general one, not specific to the problem considered, and whose essence can already be traced to the early works of van Kampen and Liftshitz on the theory of van der Waals forces, Maradudin et al. on point defects in lattices, and Mahanty and others on dispersion forces. The above formula can be deduced directly using the argument theorem in theory of contour integration.