Pump-dump mechanism

Figure 37. Electronic excitation of the NaK wavepacket from the inner turning point of the ground X state. The X A transition is considered. The initial wave packet is prepared by two quadratically chirped pulses within the pump-dump mechanism. Taken from Ref. [37].

In order to demonstrate the efficiency and robustness of the formulations presented in Sect. 5.2 and 5.3, three practical applications are considered here. In the first part of this section, we consider the complete excitation of a wavepacket from a nonequilibrium displaced position, which is directly related to the idea of bond-selective breaking, as explained in the Introduction . This is demonstrated numerically by taking diatomic molecules LiH and NaK as examples. In the second part, we consider the complete pump-dump control and creation of a localized wavepacket using quadratic chirping within the pump-dump mechanism. The bond-selective photodissociation of the H20 molecule is discussed in the third part of this subsection as an example of a multidimensional system. 

In general, the results of the calculations establish that it is possible to guide the reaction to preferentially form one or the other product with high yield. Note that, unlike the original Tannor-Rice pump-dump scheme, in which the pulse sequences that favor the different products have different temporal separations, the complex optimal pulses occupy about the same time window. Indeed, the optimal pulse shape that generates one product is very crudely like a two-pulse sequence, which suggests that the mechanism of the enhancement of product formation in this case is that the time delay between the pulses is such that the wavepacket on the excited-state... 

Using the strategy for optimal pump-dump control based on the intermediate target, we have shown that the isomerization pathway through the conical intersection can be suppressed and that optimized pulses can drive the isomerization process to the desired objective (isomer 11). This means that the complex systems are amenable to control, provided that the intermediate target exists. Furthermore, the analysis of the MD and of the tailored pulses allows for the identification of the mechanism responsible for the selection of appropriate vibronic modes necessary for the optimal control. 

The conceptual framework underlying the control of the selectivity of product formation in a chemical reaction using ultrashort pulses rests on the proper choice of the time duration and the delay between the pump and the probe (or dump) step or/and their phase, which is based on the exploitation of the coherence properties of the laser radiation due to quantum mechanical interference effects [56, 57, 59, 60, 271]. During the genesis of this field. 

An EPA survey has shown that leather tanneries typically ( rate 10 to 12 d [15] and are specialized in dyeing either grain or suede sides. The most common dyeing method applied is so-called drum-dyeing in which the dye preparation is mechanically pumped into rotation wheels. Environmental releases occur during the opening of the wheel batch and dumping the wet and rinsed dyed sides. Major dye-classes applied in the leather industry are acid dyes (which account for about 90% of the leather market), metal complex dyes and, to a lesser extent, cationic dyes. 

Dietzek B, Bruggemann B, Pascher T, Yartsev A (2006) Mechanisms of molecular response in the optimal control of photoisomeiization. Phys Rev Lett 97 258301 Dietzek B, Bruggemann B, Pascher T, Yartsev A (2007) Pump-shaped dump optimal control reveals the nuclear reaction pathway of isomerization of a photoexcited cyanine dye. J Am Chem Soc 129 13014... 

Fig. 11.4. Different harvest transport containers (Rib6reau-Gayon et al., 1977). Portable containa-s (a) 20-90 1 stackable boxes (b) 60-100 1 plastic or wooden containers (c) 600-800 1 harvesting bin (d) 1000-2000 1 high-capacity containers, transported by truck (e) 15-20 hi portable tanks. Trailers (f) 15-25 hi gravity dumping bin (g) 20-30 hi mechanical dumping bin (h) elevator dumping bin (i) screw-driven bin (j) screw-and pump-driven bin (k) pumper tank...

The compartment of the secondary circuit comprises the refuelling cavity with space to store the internal equipment and to store and inspect the SG a compartment acting as the fuel building, the RRP pools the steam dump pool for the SG discharge the zone containing the ventilation devices and the engines with mechanical inertia of the primary pumps. 

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