The most important case periodic perturbation

Such a perturbation corresponds, e.g., to an oscillating electric field of angular frequency w. 

Let us take a look at successive equations, which we obtained at the time-independent V. The only change will be, that Vkm will have the form 

The whole derivation will be therefore identical, except that the constant wkm will be replaced by w. Hence, we have a new form of the Fermi golden rule for the probability per unit time of transition from the m-th to the A -th state  

Nudear Physics, University of Chicago Press, Chicago, 1950, p. 142. the homogeneous field approximation, the field interacts with the dipole moment of the molecule (cf. Chapter 12) V x,t) = = —fi where S denotes the electric field intensity of the 

that V with expt+jwt) gives the equality E + h(o= E which means that E Em and therefore one has emission from the m-th to the A -th states. 

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Short-Time Perturbation The First-Order approach Time-Independent Perturbation and the Fermi Golden Rtde The Most Important Case Periodic Perturbation... 

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