Pulse with three potentials

For the work described in [49,50,52], bilaminar membrane hydrophones having a total thickness of 50 pm (2 x 25 pm) and active diameters of 1 mm or less were used. These hydrophones provided generally faithful reproductions of the liihotripsy pressure pulses. However, three potential problems were identified. In [52] an artifact was observed in the hydrophone waveform due to reflections at the hydrophone housing. In most cases this delayed disturbance would not interfere with the analysis of the main pulse detected by the... 

The ionisation process of the NaK dimer is investigated by applying evolution strategies to optimize the spectral phase of fs pulses interacting with the molecules. The obtained optimal pulse structure with three intensity maxima is presented. As an explanation of the ionization process a simple model of wave packet propagation on given potential energy surfaces is proposed. 

Generally our intention is to enhance the efficiency of a photochemical reaction and afterwards to translate the obtained optimal pulse texture into processes induced in the molecule. Therefore it is adequate to begin with well-known systems with simple potential energy surfaces, which will allow interpreting the results intuitively. NaK fulfills this condition as a model system very well. Additionally it can be ionized with three photons originating from fs oscillators. 

The pulse sequence with three different potentials that is usually applied for the detection of carbohydrates is shown in Figure 8.12a. However, the cleaning potential E2 being applied for 200 ms leads to an electrode recession that enlarges the cell volume as shown in Figure 8.13. This, in turn, lowers the linear speed of the liquid through the detector cell that consequently results in a decrease of the response factor for a given analyte concentration. 

Fig. B8 Virtual control panel for temperature pulse voltammetry. The curves are composed of single current samples measured at the end of heating pulses. The three resulting temperature pulse voltammograms shown correspond to three different heating temperature values encountered during the current sampling period. Equimolar solution of 5 mM ferro- and fenicyanide in 0.1 M KCl. Pt wire electrode (diameter 25 pm). Temperature values (for curves with current in increasing order) 24 °C, 64 °C and 120 °C. Potential shift with temperature (—1.6 mV K ) as well as increase of diffusion coefficient with T is visible...

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