The Hanle effect in molecules excited state

Of course, along with magnetic precession, relaxation processes take place in molecules after pulsed excitation. If the relaxation of a If-rank polarization moment is characterized by a rate constant IV, then the absolute value, i.e., Modpg of pq, diminishes over time ( decays ) exponentially  

This means that Mod pq in Eq. (4.11) now changes over time according to (4.14). It is of considerable importance here that the precession (4.11) and relaxation (4.14) are independent, in the sense that the decay does not have any effect on the change of phase ip. Simultaneous actions of turn and relaxation are shown by the broken fine in Fig. 4.1(c). This corresponds to rotation of the figure p(0, p), as presented in Fig. 4.1(6), with a simultaneous decrease in its size. 

Let us now consider continuous wave (cw) light creating a distribution of angular momenta in the excited state coherent with respect to the z-axis. The stationary distribution of angular momenta pb(6, p) may be determined by solving Eqs. (4.9) and (4.10). For bPn = 0 we obtain from 

the method of description presented in this section permits us to preserve the clarity of the picture and, at the same time, to elucidate thoroughly the essence of the phenomena connected with the effect of a magnetic field on the intensity and polarization of the radiation of a system with a large angular momentum. This is going to be the subject of the following two sections. 

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Auzinsh, M.P., Tamanis, M.Ya. and Ferber, R.S. (1987). Determination of the sign of the Lande factor of diatomic molecules in the ground and excited states by the Hanle effect, Opt. Spectrosc. (USSR), 63, 582-588. 

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