Transverse collective excitations in charged systems, cross section for magnetic neutron scattering and diamagnetic susceptibility

Modifications introduced by the transverse magnetic electron-electron interaction are discussed using a SCF technique. The diamagnetic susceptibility at Q=0 and omega =0 is nearly unchanged from the result in which this interaction is ignored. In the dynamical case, however, the screening action is important and determines the frequencies of the transverse collective modes. It is shown that the excitation spectrum of these modes is directly related to the cross section for magnetic neutron scattering. Detailed information on the dispersion and lifetime of the transverse collective excitations as well as of the single particles in charged systems may be obtained by such experiments.