Complete pump-dump control

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. 

The numerical results shown in Fig. 6.2 confirm that the rotation direction of n electrons temporally changes between clockwise and counterclockwise in the case of a single-pulse control. Switching of the rotation direction can be prevented efficiently, and unidirectional rotation of Jt electrons can be realized consecutively in a simple manner. In the three-level model analysis in a short-pulse limit, as already stated, the pulse with e+ (e ) creates a coherent superposition L) - - H) ( L) — H)), and L) - - H) created by a pump pulse with e+ evolves as L) - - H) L) — i H). Then the population in —) can be dumped to G) by applying a dump pulse with e just after the created state has completely shifted as L) — i H) L) — H). Thus, only clockwise rotation can be generated. Figure 6.3 shows the results of a pump-dump control simulation of an R enantiomer of DCPH. The values of the parameters of the pump pulse were/ = 2.24 GVm i, = 19.4 fs, co = 7.72 eVM, and e = e+, and those of the dump pulse were / = 2.37 GVm , tj = 19.4 fs, co = 7.72 eV/h, and e = e. The delay time between the pulses was 19.4 fs. 

The second example is the quadratically chirped pump-dump scheme. Since the pioneering work by Tannor and Rice [119], the pump-dump method has been widely used to control various processes. However, since it is not possible to transfer a wave packet from one potential energy surface to another nearly completely by using the ordinary transform limited or linear chirped pulses, the... 

Summary. An effective scheme for the laser control of wavepacket dynamics applicable to systems with many degrees of freedom is discussed. It is demonstrated that specially designed quadratically chirped pulses can be used to achieve fast and near-complete excitation of the wavepacket without significantly distorting its shape. The parameters of the laser pulse can be estimated analytically from the Zhu-Nakamura (ZN) theory of nonadiabatic transitions. The scheme is applicable to various processes, such as simple electronic excitations, pump-dumps, and selective bond-breaking, and, taking diatomic and triatomic molecules as examples, it is actually shown to work well. 

The remainder of this paper is organized as follows In Sect. 5.2, we present the basic theory of the present control scheme. The validity of the theoretical method and the choice of optimal pulse parameters are discussed in Sect. 5.3. In Sect. 5.4 we provide several numerical examples i) complete electronic excitation of the wavepacket from a nonequilibrium displaced position, taking LiH and NaK as examples ii) pump-dump and creation of localized target wavepackets on the ground electronic state potential, using NaK as an example, and iii) bond-selective photodissociation in the two-dimensional model of H2O. A localized wavepacket is made to jump to the excited-state potential in a desirable force-selective region so that it can be dissociated into the desirable channel. Future perspectives from the author s point of view are summarized in Sect. 5.5. 

The plant comprised the wind turbine, the electrolyser unit complete with its built-in controllable power supply, battery storage, a DC-DC controllable converter, and two dump loads (0.5 and 2 kW) controlled by two voltage-actuated relays. The auxiliary equipment (electrolyser pumps, valves, control equipment, and water demineralisation unit) for the demonstration plant were supplied by the grid for convenience. 

H. J. Neusser Choosing a special pulse sequence of the dump and the pump laser pulse leads to a complete blocking of the population transfer in the CIS experiment or else makes it very efficient. We can say that a special channel is open or closed, that is, controlled by the experimental parameter. This is similar to STIRAP experiments. However, it was shown by Band and Magnes [1] that the adiabatic passage population transfer in STIRAP experiments does not represent a solution of an optimal control problem. 

A. Reactor Checkout To assure safe operation of the reactor, a prescribed sequence of operations must be followed to start the reactor. This sequence, which is invariantly set by electrical interlocks in the control console, is briefly as follows (1) neutron source in, (2) the three safety rods completely withdrawn, (3) water-dump valve closed, (4) water pumped to operating level, and (5) the control rods moved to the desired positions. 

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