Kinetic equation for collective modes of a Fermi system with free surface

Kinetic-theory approach to low-energy collective modes in nuclei

“…[5] in order to determine the pole structure of the additional term in the boundary condition (2.13).…”

“…In Ref. [5] an approach similar to that of Ref. [3] has been followed, but with boundary conditions that are inspired by the Goldhaber-Teller (GT), rather than by the SJ model.…”

“…Then we consider the condition determining the eigenfrequencies of collective modes that has been derived in Ref. [5]. Since in that paper this condition has been studied in detail only for monopole (L = 0) oscillations, we turn our attention to the lowest isoscalar modes with L > 0.…”

“…In Ref. [5] it has been argued that the effects of moving boundary can be taken into account, at least in a linearized approximation, simply by changing the boundary conditions (2.8). In particular, since we are interested in the radial motion of nucleons in the effective potential U 0 (r) + λ 2 mr 2 , it is sufficient to change the boundary condition at one turning point (say x 2 ).…”

“…In particular, since we are interested in the radial motion of nucleons in the effective potential U 0 (r) + λ 2 mr 2 , it is sufficient to change the boundary condition at one turning point (say x 2 ). Thus, instead of the boundary conditions (2.8), in [5] the following boundary conditions have been used…”