Temperature-jump technique Applications

The Raman laser temperature-jump technique has been used in studies of a variety of spin-equilibrium processes. It was used in the first experiment to measure the relaxation time of an octahedral spin-equilibrium complex in solution (14). Its applications include investigations of cobalt(II), iron(II), iron(III), and nickel(II) equilibria. 

Robinson, B. H. (1975). The stopped-flow and temperature-jump techniques-principles and recent advances. In Chemical and Biological Applications of Relaxation Spectrometry (E. Wyn-Jones, ed.), pp. 41-48. Reidel Publ., Dordrecht, The Netherlands. 

This value has been supported by later work (a) with the microwave temperature-jump technique (G. Ertl and H. Gerischer, Z. Elektrochem. 65 (1961) 629 Z. Elektrochem. 66 (1962) 560) and (b) by infrared iodine-laser initiation (D.M. Goodall, R.C. Greenhow, B. Knighf J.F. Holzwarth and W. Frisch, in W.J. Gettins and E. Wyn-Jones (Eds.), Techniques and Applications of Fast Reactions in Solution, Rei-del, Dordrecht, 1979, p. 567) see, also (c) W.J. Albery, Prog. React. KineL 4 (1%7) 353. 

Instead of continuous modulation, single thermal pulses have been imposed by laser beams. This can be seen as a continuation and an expansion of the temperature-jump technique which had been introduced to study kinetics of ionic processes [36]. The method has found application preferably with single-crystal electrodes [65-70]. Many fundamental quantities have been determined, among them the potential of zero charge (Fpzc) of Au(l 11) [65], the potential of maximum entropy [66, 70], the process of hydrogen adsorption at platinum surfaces [67, 68] and the entropy of double-layer formation [69]. This quantity also has been... 

This report has been written in order to demonstrate the nature of spin-state transitions and to review the studies of dynamical properties of spin transition compounds, both in solution and in the solid state. Spin-state transitions are usually rapid and thus relaxation methods for the microsecond and nanosecond range have been applied. The first application of relaxation techniques to the spin equilibrium of an iron(II) complex involved Raman laser temperature-jump measurements in 1973 [28]. The more accurate ultrasonic relaxation method was first applied in 1978 [29]. These studies dealt exclusively with the spin-state dynamics in solution and were recently reviewed by Beattie [30]. A recent addition to the study of spin-state transitions both in solution and the... 

The most significant results obtained for complexes of iron(II) are collected in Table 3. The data derive from laser Raman temperature-jump measurements, ultrasonic relaxation, and the application of the photoperturbation technique. Where the results of two or three methods are available, a gratifying agreement is found. The rate constants span the narrow range between 4 x 10 and 2 X 10 s which shows that the spin-state interconversion process for iron(II) complexes is less rapid than for complexes of iron(III) and cobalt(II). 

The dynamics of intercalation of small molecules with DNA, groove binding and binding to specific sites, such as base pair mismatches have been studied by stopped-flow,23,80 108 temperature jump experiments,26,27,94 109 120 surface plasmon resonance,121 129 NMR,86,130 135 flash photolysis,136 138 and fluorescence correlation spectroscopy.64 The application of the various techniques to study the binding dynamics of small molecules will be analyzed for specific examples of each type of binding. 

A number of soil chemical phenomena are characterized by rapid reaction rates that occur on millisecond and microsecond time scales. Batch and flow techniques cannot be used to measure such reaction rates. Moreover, kinetic studies that are conducted using these methods yield apparent rate coefficients and apparent rate laws since mass transfer and transport processes usually predominate. Relaxation methods enable one to measure reaction rates on millisecond and microsecond time scales and 10 determine mechanistic rate laws. In this chapter, theoretical aspects of chemical relaxation are presented. Transient relaxation methods such as temperature-jump, pressure-jump, concentration-jump, and electric field pulse techniques will be discussed and their application to the study of cation and anion adsorption/desorption phenomena, ion-exchange processes, and hydrolysis and complexation reactions will he covered. 

The objective of this chapter is to discuss the theory of chemical relaxation and its application to the study of soil chemical reaction rates. Transient relaxation techniques including temperature-jump (t-jump), pressure-jump (p-jump), concentration-jump (c-jump) and electric-field pulse will be discussed both as to their theoretical basis and experimental design and application. Application of these techniques to the study of several soil chemical phenomena will be discussed including anion and cation adsorp-tion/desorption reactions, ion-exchange processes, hydrolysis of soil minerals, and complexation reactions. 

The behavior of interfacial water molecules on platinmn single-crystal electrodes, under electrochemical conditions, has been characterized for the first time by means of the laser-induced temperature jump method. The fundamentals of this method and the proposed interpretation of the experimental results will be described in Section V.l and V.2. Then, recent results on the three platinum basal planes will be discussed in Section V.3. Afterwards, the application of this technique to Pt(lll) stepped surfaces will be explained in Section V.4. And finally, results on the effect of the chemical modification of the surface composition of Pt(l 11) by adatom deposition will be presented in Section V.5. 

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