Alignment and orientation of an adsorbed dipole molecule

Half-cycle laser pulse is applied on an absorbed molecule to investigate its alignment and orientation behavior. Crossover from field-free to hindered rotation motion is observed by varying the angel of hindrance of potential well. At small hindered angle, both alignment and orientation show sinusoidal-like behavior because of the suppression of higher excited states. However, mean alignment decreases monotonically as the hindered angle is increased, while mean orientation displays a minimum point at certain hindered angle. The reason is attributed to the symmetry of wavefunction and can be explained well by analyzing the coefficients of eigenstates.Comment: 4 pages, 4 figures, to appear in Phys. Rev. B (2004

Bosonization for 2D Interacting Fermion Systems: Non-Fermi Liquid Behavior

Non-Fermi liquid behavior is found for the first time in a two-dimensional (2D) system with non-singular interactions using Haldane's bosonization scheme. The bosonized system is solved exactly by a generalized Bogoliubov transformation. The fermion momentum distribution, calculated using a generalized Mattis-Lieb technique, exhibits a non-universal power law in the vicinity of the Fermi surface for intermediate interaction strengths.Comment: 13 pages, 2 figures upon request, latex. (to appear in Mod. Phys. Lett. B