Adiabatic approximation passage

It should be noted that the adiabatic approximation may be violated during the passage of the region x x. if the nuclear velocity dx/dt is high. However, this approximation is certainly valid outside it, i.e., in the initial and final states of the system. Under these conditions can be evaluated using the quasiclassical method of... 

In the presence of radiofrequency irradiation, relaxation of magnetization aligned with the effective magnetic field is characterized by the time constant Tip. On the other hand, the time constant T2p. characterizes the relaxation of magnetization that is perpendicular to the effective field. Michael et showed that T2p can be measured directly with Carr Purcell sequences composed of a train of adiabatic full-passage (AFP) pulses. During adiabatic rotation T2p characterizes the relaxation of the magnetization, which under adiabatic conditions remains approximately perpendicular to the time-dependent effective field. Theory is derived to describe the influence of chemical... 

For adiabatic reaction pathways (i.e. Kel = 1) the nuclear frequency factor, vn (s 1), represents the rate at which reacting species in the vicinity of the transition state is transformed into products. This frequency will be influenced by a combination of the various motions associated with the passage of the system over the barrier, approximately weighted according to their relative contributions to the activation energy. These motions usually involve bond vibrations and solvent motion, associated with the characteristic inner- and outer-shell frequencies, vis and vos, respectively. A simple formula for vn which has been employed recently is [la, 7]... 

The adiabatic passage induced by two delayed laser pulses, the well-known process of STIRAP [69], produces a population transfer in A systems (see Fig. 7a). The pump field couples the transition 1-2, and the Stokes field couples the transition 2-3. It is known that, with the initial population in state 11), a complete population transfer is achieved with delayed pulses, either (i) with a so-called counterintuitive temporal sequence (Stokes pulse before pump) for various detunings as identified in Refs. 73 and 74 or (ii) with two-photon resonant (or quasi-resonant) pulses but far from the one-photon resonance with the intermediate state 2), for any pulse sequence (demonstrated in the approximation of adiabatic elimination of the intermediate state [75]). Here we analyze the STIRAP process through the topology of the associated surfaces of eigenenergies as functions of the two field amplitudes. Our results are also valid for ladder and V systems. 

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