Experimental Arrangement

Further details of Mossbauer spectrometers, including various design tricks used to solve experimental problems, are given in [1] and [5-7]. Reference [1] is a comprehensive modern book the others are older but simpler, and include many inorganic applications. There are, of course, many other books on the subject. 

Typical Mossbauer spectrum with fitted contributions. The Fe Mossbauer spectrum of the reduced form of the terminal dioxygenase protein of benzene dioxygenase from Pseudomonas putida was recorded at 195 K. Adapted with permission, from [4]. Copyright the Biochemical Society. 

---

Figure 2. Schematic of the experimental arrangement used for inspection of aluminium plate. Lenses are shown as LI and L2, mirrors as Ml, M2 and M3, and liquid crystal cell as LC...

Experimental arrangement for recording a potentiometric redox titration curve. 

Figure 5.13 shows a typical experimental arrangement for obtaining the Raman spectmm of a gaseous sample. Radiation from the laser source is focused by the lens Lj into a cell containing the sample gas. The mirror Mj reflects this radiation back into the cell to increase... 

Figure 5.13 Experimental arrangement for gas phase Raman spectroscopy.

Figure 9.22 Experimental arrangement for coherent anti-Stokes Raman scattering...

In general, according to Eq. (2-10), two electrochemical reactions take place in electrolytic corrosion. In the experimental arrangement in Fig. 2-3, it is therefore not the I(U) curve for one reaction that is being determined, but the total current-potential curve of the mixed electrode, E,. Thus, according to Eq. (2-10), the total potential curve involves the superposition of both partial current-potential curves ... 

Older experimental arrangements used Earaday cups with small apertures mounted on goniometers, which could be moved around the sample to collect the back-scattered electron current directly, or spot photometers, which were directed at one dif-... 

Fig. 3.3. Experimental arrangement used by Krauss and Gruen for SSIMS [3.8] a qua-drupole mass spectrometer was used for mass analysis and a retarding-field analyzer for prior energy selection (a) ion gun (b)-(d) lenses 1-3 (e) quadrupole mass spec-...

Fig. 4.33. Schematic diagram of the experimental arrangement for GXRR measurements. Beam-conditioning optics can include slits.

To achieve pressures intermediate to those achieved by direct contact with a given metal plate, use is often made of alternate layers of various shock impedance materials. Table 3.2 gives a summary of experimental arrangements that have been used in materials studies to achieve pressures from 3 to 80 GPa. 

Fig. 3.5. The experimental arrangement used for a typical compressed gas gun is shown. The apparatus is designed to impact a selected impactor upon a target material with precision on the alignment of the impacting surfaces. Velocity at the impact surface can be measured to an accuracy and precision of 0.1%. This loading produces the most precisely known condition of all shock-compression events.

The piezoelectric behavior of both quartz and lithium niobate has been studied in a series of careful, systematic investigations. (See Graham and coworkers [65G01, 70101, 75G04].) The experimental arrangement is shown Fig. 4.2. The impactor, preferably the same material as the piezoelectric sample (but perhaps another standard material), is accelerated to a preselected... 

To examine the response of PVDF to a higher pressure, ramp-type loading, an experimental arrangement with a ceramic Pyroceram similar to that of the fused quartz loading was employed. In this case, the loading wave transmitted through the Pyroceram is only approximately known and a simultaneous measurement must be carried out of the wave transmitted through the pyroceram and the response of the PVDF. 

Fig. 19.34 Experimental arrangement for corrosion tests without heat transfer, (a) Test vessel and specimen, (b) specimen assembly for single metal or bimetal specimens, and (c) assembly for brass/solder/brass specimens...

A preferable experimental arrangement, which eliminates both of the above disadvantages, is the so-called frequency-sweep N.M.D.R. experiment. Here H0 is kept constant at all times, o>2 is located on the center of the resonance to be irradiated and then the spectrum is observed by slowly sweeping o>i through the spectrum. Since a>2 remains at all times on the center of the resonance to be decoupled, this experiment enables one to remove simultaneously all of the couplings caused by that particular resonance. All of the experiments discussed below were performed under these conditions. 

Figure 6-23. Sketch of the experimental arrangement tor measuring the angular dependence or lluores-ccncc and electroluminescence. The viewing angle 0 is varied between -90 " and +90 .

In many respects the time-resolved pump-probe technique is similar to the CW counterpart. The use of pulsed laser light permits direct probing of both the magnitude of the PA and its dynamics. The experimental arrangement is practically the same as for the CW version, i.e., both pump and probe beams are focused and overlapped onto same spot on a sample. In addition, the pump and probe pulses are synchronized so that the lime interval t between them is constant and confined to a certain time range (in our case up to 3 ns). 

A series of experiments have been undertaken to evaluate the relevant thermodynamic properties of a number of binary lithium alloy systems. The early work was directed towards determination of their behavior at about 400 °C because of interest in their potential use as components in molten salt batteries operating in that general temperature range. Data for a number of binary lithium alloy systems at about 400 °C are presented in Table 1. These were mostly obtained by the use of an experimental arrangement employing the LiCl-KCl eutectic molten salt as a lithiumconducting electrolyte. 

Fig. 1-5. Transmittance as a function of the thickness of absorber. The two curves for the transmittance of monochromatic x-rays are pure exponentials. The curve for the transmittance of mixed x-rays is the sum of two exponential curves. The experimental arrangement is shown in Fig. 1-4.

Barkla, originally interested mainly in v-ray scattering, discovered characteristic x-rays by an experimental method similar in principle to that described above. His experimental arrangement (Figure 1-7) is reminiscent of that used today in studies of the Raman effect. By using an absorber in the form of sheets (Figure 1-7) to analyze the scattered beam in the manner of Figure 1-4, he obtained results that clarified the earlier experiments described above. 

When the temperature of the analyzed sample is increased continuously and in a known way, the experimental data on desorption can serve to estimate the apparent values of parameters characteristic for the desorption process. To this end, the most simple Arrhenius model for activated processes is usually used, with obvious modifications due to the planar nature of the desorption process. Sometimes, more refined models accounting for the surface mobility of adsorbed species or other specific points are applied. The Arrhenius model is to a large extent merely formal and involves three effective (apparent) parameters the activation energy of desorption, the preexponential factor, and the order of the rate-determining step in desorption. As will be dealt with in Section II. B, the experimental arrangement is usually such that the primary records reproduce essentially either the desorbed amount or the actual rate of desorption. After due correction, the output readings are converted into a desorption curve which may represent either the dependence of the desorbed amount on the temperature or, preferably, the dependence of the desorption rate on the temperature. In principle, there are two approaches to the treatment of the desorption curves. 

---