We determine the semiclassical energy levels for the \phi^4 field theory in
the broken symmetry phase on a 2D cylindrical geometry with antiperiodic
boundary conditions by quantizing the appropriate finite--volume kink
solutions. The analytic form of the kink scaling functions for arbitrary size
of the system allows us to describe the flow between the twisted sector of c=1
CFT in the UV region and the massive particles in the IR limit. Kink-creating
operators are shown to correspond in the UV limit to disorder fields of the c=1
CFT. The problem of the finite--volume spectrum for generic 2D Landau--Ginzburg
models is also discussed.Comment: 30 pages, 10 figure