State weak mixing

In Fig. 5. The structure of the negative parity states is as follows. The low lying 3 and 5 states appear to be rather complicated as their population does not follow the (2J+1) population expected for a simple multiplet. In contrast, the 7 , 9 and 10 appear to have equivalent f7/2 il3/2 strength and thus have rather simple structure. On the %other hand, no evidence is found for the 4 or 8 states and only weak evidence that the state at 3.3 MeV is a 6 state. Configuration mixing is a possible, though not a certain, reason for the absence of these states. In any case, there does not appear to be a simple vf7/2 v13/2 multiplet. 

It should be noted that the above classification of the electroabsorption spectrum is valid only approximately, because first of all eqn (11.11) is correct only in the case of weak absorption and, second, the Frenkel and CT exciton states usually mix. We finally mention that the change of the refractive index Sn is of the same order as 5k new experimental techniques are required to measure this change, however. Good candidates for such methods have been proposed by War-man and coworkers (18). The success of such measurements could be the basis of electrorefraction spectroscopy, complementary to the existing electroabsorption spectroscopy. 

Here K i = K/ are again given by (19) with y / defined by (11) (including the rotational relaxation contribution). Again these rate constants are proportional (in the very weak mixing limit) to the mixing coefficient of the initially excited state and show a linear dependence on as long as... 

By definition, weak mixing is taken to occur in situations where a one-to-one correspondence between each zero-order state n> and one resonant state v> can be assumed, and where standard perturbation theory applies. The absolute energy variation due to mixing must therefore be smaller than the zero-order level spacing Se = e +i — e ... 

Consider first the cases of weak mixing. By definition, the eigenvalues remain in the neighborhood of the zero-order values E and can be evaluated by a perturbation calculation. For the resonant state (t> near the radiant state s>, one simply gets to first order (see, e.g., Voltz, 1974) ... 

The short-time behavior of the system is essentially the same as in the statistical limit, but differs by the residual s character of the finally attained mixed states. In the statistical case, however, the s character of the initially excited state is irreversibly lost. This difference is due to a discrete-level structure of the /i manifold in the strong-coupling case, as compared to the statistical quasi-continuum. The deviation from the purely statistical behavior will therefore be attenuated, when /-level density or /-level width increases. In the first case, since N p, the relative intensity of the long component in decay ( 1/N) will be reduced. In the latter, not only its amplitude but also its decay time decreases because of the weak-mixing effect. In both situations, the detection of the long decay component becomes more and more difficult when a strong /-level overlapping transforms the discrete / manifold into a statistical quasi-continuum. 

There is no doubt that the Si - Sq fluorescence of molecules with a nonffuorescent S, state, such as azulene and its derivatives (Binsch et al., 1967), xanthione, and thioxanthione (Mahaney and Huber, 1975), corresponds to the latter ease. Since y > F, we are in the statistical limit because of the weak-mixing effect, even for low p, values. 

The weak-mixing effect must be taken into account for high collider pressures such that v states strongly overlap. It may play an important role as well for diatomic molecules, as in the strong coupling case. 

W boson. This is interpreted as a signature that the weak interaction mixes the quark states. It is sufficient to assume that either the upper or the lower quark states are mixed. The lower quark states are taken to be mixed, and that is indicated by the apostrophes in O Table 10.1 on the symbols of the lower quarks. There is experimental evidence, neutrino oscillations, for the neutrinos also having a tiny little mass (Fukuda and et al. 1998) then of course the lepton states will be mixed as well for the weak interaction (Maid et al. 1962). 

---