ABSTRACT
The radiation-matter interaction Hamiltonian associated with any arbitrary thirdorder response spectroscopy is therefore given as
H t t t trad mat-( ) ˆ ( , ) ˆ ( , ) ˆ ( ,= - ⋅ - ⋅ - ⋅V F r V F r V F r1 1 2 2 3 3 ). (5.1)
From the definition of the generalized third-order response spectroscopy, the signal field amplitude (intensity) should be linearly proportional to each external field amplitude Fj (intensity |Fj|2). Depending on the choice of the three effective radiation-matter interaction Hamiltonians, there are a number of different third-order multidimensional spectroscopic methods in general. Among them, only a few simple cases will be discussed in detail in this chapter, but the other methods probing thirdorder molecular responses can be easily explored by using the general theoretical framework presented in this chapter.
