Probing of alignment and orientation using electric-dipole-forbidden transitions

Abstract

The probing of aligned and oriented molecules or atoms by electric quadrupole and magnetic dipole transitions is described using the spherical tensor formalism. The case of cylindrical symmetry is treated explicitly. It is shown how moments of the initial angular momentum distribution up to rank 4 are obtainable using electric quadrupole radiation. The interference between electric quadrupole and magnetic dipole transitions is also treated.