Quantum beat modulation depth

The eigenvector matrix C can be determined from relative values of quantum beat modulation depths, together with conditions associated with the fact that C is orthonormal. The first step is to work with an a-type decay and to note that... 

At this point it is worth noting that there are relations associated with the orthogonality of C and with absolute quantum beat modulation depths that also can be used to find the elements of C. Clearly, from the above, one may not need these relations. However, the analysis we have presented presumes that a good deal of high-quality experimental data are available. This may not always be the case. When it is not, these extra relations may be particularly useful. They are useful, in any case, in providing consistency checks on the elements calculated for the matrix. 

At 1400 cm of excess energy in anthracene, we observed quantum beats in the dispersed fluorescence with a large modulation depth. The beats modulation depth is sensitive to the excess energy and to the fluorescence detection wavelength. 

The situation changed, however, with two advances. The first advance was the discovery that in the S, - S0 spectrum of jet-cooled anthracene a second band exists (at S, + 1420 cm-1), the excitation of which gives rise to quantum beat-modulated fluorescence decays.40 Besides indicating a somewhat more global importance to the beat phenomenon in anthracene, the characteristics of these new beats provided very strong evidence that they arose as a manifestation of IVR. In particular, the beats were shown to have phases and modulation depths dependent on the fluorescence band detected. Such behavior, which... 

Other excitation energies Other than the ones at S, + 1380 and S, + 1420 cm-, there are three prominent bands in the intermediate region of jet-cooled anthracene s excitation spectrum. Time- and frequency-resolved measurements subsequent to excitation of these bands have also been made. Without going into any detail concerning the results of these measurements, we do note that all three excitations give rise to quantum beat-modulated decays whose beat patterns (phases and modulation depths) depend on the fluorescence band detected.42 Figure 16 shows an example of this behavior for excitation to S, + 1514 cm-1. The two decays in the figure correspond to the detection of two different fluorescence bands in the S, + 1514 cm-1 fluorescence spectrum. 

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