Contrary to optics, understanding the propagation of an elementary excitation
requires replacing the single body description by a many body one.
Electronic [pi] [right arrow] [[pi].sup.*] excitations are subsequently introduced by using configuration interaction (singles) (CI-S) theory where we write the excited state wave function as a linear combination of elementary excitations
between occupied and unoccupied molecular orbitals
By measuring the spectrum of elementary excitations
, one reveals the symmetries and interactions inherent in a physical system.
Their topics include the thermodynamics of surface phenomena, localized states and surface elementary excitations
, calculating adhesion characteristics of metals and their melts by the density functional method, friction of surfaces of solids with no lubrication, and ferromagnetism in ultrathin films of transition metals.
This parabola crosses the Landau-Feynman dispersion curve for elementary excitations
in superfluid [.sup.4]He at 2[pi]/k* = 0.89 nm and E* = h[omega] = 12 K.
of Parma, Italy) examines the elementary excitations
in magnetic periodic structures, the spin waves or magnons, which are shown to behave like an ideal Bose gas at low temperature and an interacting Bose system at higher temperature.
Raman scattered light originates from objects related to atoms and molecules in matter, such as chemical bonds in molecules and the elementary excitations
in solids, says Zhang (physics, Peking U.), so Raman spectroscopy has no trouble studying nanostructures directly.