Ground state effects in fluorescence

At Q-absorption and under very strong depopulation (x — oo) only one term remains in Eqs. (3.13) and (3.14), where n = M = 0. One may therefore obtain limiting values of Vq/Vq, similar in meaning to the classical ones presented in Table 3.3, but with arbitrary values of J . The o/ o and Vo/Vo values, as calculated in this way, are given in Table 3.4. 

in this section we have described the manner in which absorption of light by a molecule leads to polarization of the angular momenta of the absorbing level. We have also shown how to calculate the multipole moments created on the lower level. It is important to stress that the adopted model of description enables us to obtain precise analytical expressions for the multipole moments, including both cases, namely those for arbitrary values of angular momenta and those for the classic limit J — oo. Our subsequent discussion will concern problems connected with the manifestation of ground state angular momenta anisotropy in experimentally observable quantities. 

As has been proved in earlier experiments it is much easier to apply the laser-induced fluorescence method of detection. Indeed, if we observe, for instance, fluorescence from an excited level in the cycle a — b — c (see Fig. 1.2), then the anisotropy of angular momenta Ja distribution will manifest itself in b — c emission. 

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