A fully two-dimensional study of the electronic sub-bands in crescent-shape
d quantum wires is presented. The confinement energies and the wave functio
ns are compared by means of an aspect ratio to those produced by the adiaba
tic approximation. Guidelines for applying the adiabatic model are provided
and the adiabatic quantum number classification scheme is discussed. "Non-
adiabatic" states are determined among the first few sub-bands and a built-
in dipole is identified. The energy spectrum is explored as a function of w
ire dimensions achievable by present-day technology. Wire parameters corres
ponding to maximized sub-band separations are determined.