Multidimensional systems theoretical analyses

In this chapter we surveyed the theoretical analysis of resonant multidimensional spectroscopies generated by the interaction of 3 fs pulses with a Frenkel exciton system. Closed expressions for the time-domain third-order response function derived by solving the NEE are given in terms of various exciton Green functions. Alternatively, the multidimensional time-domain signal can be calculated starting from the frequency domain the third-order... 

As the interest of the researchers is shifting toward the role of CIs in photochemical systems, theoretical developments will be necessary to work out Hamiltonians and computational techniques to treat multidimensional systems with large-amplitude motions and dissipative channels. Detailed interpretations of Cl effects in photochemistry will call for more sophisticated and innovative approaches, because the ones utilized up to now are suitable for small molecules. Whether CW spectra analysis is a suitable tool... 

There have been extensive experiments on the isomerization of stilbene and its derivatives (125, 126), none of which to date have received any serious theoretical numerical analysis. In this experiment, changes in pressure have caused changes of orders of magnitude in the rate. It is time that a serious molecular dynamics study of this system be undertaken. This might also be useful in understanding the importance of multidimensional effects, since typically, in an isomerization of a big molecule, one could expect that more than one angle participates strongly in the isomerization process. 

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