The polarization of the resonance fluorescence of interacting atoms and the transfer of coherence, due to the exchange of excitation, are studied theoretically. The treatment is for the general case where both the excited and the ground states can have arbitrary angular momenta, except that they can be connected to each other by an allowed transition. Electrostatic dipolendash;dipole interaction and electromagnetic radiative interaction are considered simultaneously as the perturbations on the system. Heitler and Ma's generalized timehyphen;dependent perturbation method is used. The system is quantized with respect to the spacehyphen;fixedzaxis and a static magnetic field along thezaxis may be present, so that the magnetic sublevels (m, mprime;, etc., for the excited stateJ, andagr;, bgr;, etc., for the ground stateJprime;) are not necessarily degenerate. The intensity of the scattered light of a given polarization, in a given direction, is expressed as a function ofkR(whereplanck;ckis the energy of excitation andRis the internuclear distance), and of the orientation ofRwith respect tozaxis. The matrix elementslpar;planck;thinsp;sol;thinsp;2rpar;ggr;mbgr;,agr;mprime;andVmbgr;,agr;mprime;, which cause resonant transfer of excitation between two atoms through radiative and electrostatic interaction, respectively, are also expressed as a function ofkR, and of the orientation ofR. For randomly oriented atoms, the polarization after being averaged over the random orientation ofRbecomes a function ofkR. Numerical calculations have been carried out for1S0thinsp;rarr;thinsp;1P1transition. The coherence is shown to be conserved upon resonant transfer of excitation whenRis parallel to the quantization axis.
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