EMERGENCE OF CIRCULARITY AT LINEAR POLARIZED EXCITATION OF MOLECULES

General conditions causing partial transformation of optical alignment of excited state angular momenta J into orientation at weak linear po larized broad line excitation of molecules are examined. As is shown, the phenomenon takes place under the effect of an external perturbing factor leading to such magnetic sublevel M splitting omega(MM') when o mega(MM+/-1) not-equal omega(-M-/+1-M) and omega(MM') is of the order of molecular state relaxation rate. An analytical expression is obtain ed describing the appearing circularity of fluorescence for arbitrary J values. A numeric example is given for 1SIGMA state molecules with J =10 assuming a quadratic Stark effect in a homogeneous external electr ic field.