Manifestation of anisotropic collisional generation of higher polarizationmoments in polarization of quadrupole emission

Direct observability of polarization moments of a higher order-octupole ori entation of atomic angular momenta (kappa = 3) and their hexadecapole align ment (kappa = 4)-from polarization of quadrupole radiation is discussed. Th e case when atoms are excited through dipole absorption of light producing orientation or alignment of angular momenta with kappa = 1 or 2 and higher polarization moments are induced by collisions with a beam of particles is considered. It is shown that differences in the laws of transformation of p olarization moments of various ranks kappa in rotations of coordinate axes allow us to select the pure contribution of the higher polarization moment under study from the signal of polarization of quadrupole emission by exclu ding the contribution of orientation or alignment with kappa = 1 or 2. Opti mum systems of coordinate axes for the observation of octupole orientation from circular polarization of light and for the observation of hexadecapole alignment from linear polarization of light, in which the pure contributio n of the higher polarization moment under study to polarization of quadrupo le emission reaches its maximum, are calculated. (C) 2000 MAIK "Nauka/Inter periodica".