Probe beam deflection PBD

The term photothermal deflection is used as an equivalent to probe beam deflection the term optical beam deflection has been used only infrequently. 

For most binary electrolyte solutions 9n/9c is constant. Since both the length of the pathway where the laser beam is influenced by the concentration gradient and the refractive index n of the solution are constant, the deflection depends practically only on 9c/9c [867]. 

Instrumentation. The experimental setup is simple and straightforward. The electrochemical interphase to be investigated is mounted inside an electrochemical cell that allows a beam of light (usually laser light, which is provided most commonly by HeNe gas ion lasers adjusted to a typical diameter of 80 pm) to enter the cell and pass the solution phase parallel and as close to the electrode surface as possible. The exciting beam arrives at a position sensitive detector that indicates any deflection of the beam as a function of electrode potential. The setup is shown in Fig. 5.139. 

A scanning refractometer that is basically very similar to the setup described in detail above has been reported by Tamor and Zanini [874], The laser beam scans the electrolyte solution volume close to the electrode surface. Data on beam position and refracted beam incidence were used to calculate local refractive indices as a function of distance from the electrode, eurrent density, etc. 

Probe beam deflection can be observed during metal deposition and dissolution. The method is sensitive towards changes in the concentration gradient originating from dissolution or deposition of submonolayer amounts of material on the electrode surface [875]. A typical result of PBD measurements is displayed in Fig. 5.140. The negative PBD response observed during anodic stripping of the silver indicates concentration decay into the solution phase. The positive response 

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EQCM can be combined with other techniques, e.g., with -> probe beam deflection (PBD) [viii], radiotracer methods (- tracer methods) [ix], and - scanning electrochemical microscopy [x]. 

The term mirage effect has been indistinctly assigned to studies performed by - photothermal deflection spectroscopy (PDS) and - probe beam deflection (PBD). However, PDS is based on the analysis of the first term of the last equation, whilst in PBD, essentially the second term is evaluated. 

Probe beam deflection (PBD) — An in-situ electrochemical technique employed to study the mass fluxes... 

The quartz crystal nanobalance (QCN) can be combined with practically any electrochemical methods, such as cyclic voltammetry, chronoamperometry, chronocoulometry, potentiostatic, galvanostatic, rotating disc electrode [11], or potentiometric measurements. The EQCN can be further combined with other techniques, e.g., with UV-Vis spectroscopy [12], probe beam deflection (PBD) [13], radiotracer [14], atomic force microscopy (AEM) [15], and scanning electrochemical microscopy (SECM) [16]. The concept and the instrumentation of... 

The application of combinations of electrochemical methods with non-electro-chemical techniques, especially spectroelectrochemistiy (UV-VIS, FITR, ESR), the electrochemical quartz crystal microbalance (EQCM), radiotracer methods, probe beam deflection (PBD), various microscopies (STM, AFM, SECM), ellipsometiy, and in situ conductivity measurements, has enhanced our understanding of the nature of charge transport and charge transfer processes, stmcture-property relationships, and the mechanisms of chemical transformations that occur during charg-ing/discharging processes. 

The probe beam deflection (PBD) technique (optical beam deflection or the mirage technique) is based on the measurement of refractive index gradients in front of the electrode I electrolyte interface [10,155,193,261-281]. 

The results obtained by different techniques (radiotracer [80, 84], quartz crystal microbalance [73-76, 78, 83, 85-87, 90, 92-110], probe beam deflection (PBD) [88-90], etc.) have revealed that the situation may further be complicated. It has... 

Calvo and Etchenique summarized in their review some further in situ combinations of EQCM with non-electrochemical techniques (see [35] and references therein). For example, EQCM was also combined with ellipsometry in order to study the nucleation and growth of polyaniline films (reference 24 in [35]) or the viscoelastic behavior of poly(7-methyl-L-co y-n-octadecyl-L-glutamate) [17]. EQCM was combined with UV-visible absorption spectroscopy, in order to investigate the redox reactions of viologens. A combination of EQCM and probe beam deflection, PBD, was also reported in the literature (references 29, and 30 in [35], and [81]). PBD can discriminate between anion, cation, and solvent fluxes that might be generated on the electrode surface. 

Henderson Ml, Hillman AR, Vieil E, Lopez C (1998) Combined electrochemical quartz microbalance (EQCM) and probe beam defection (PBD) validation of the technique by a study of silver ion mass transport. J Electroanal Chem 458 241-248 Henderson MJ, Hillman AR, Vieil E (1999) Ion and solvent transfer discrimination at a poly(o-toluidine) film exposed to HC104 by combined electrochemical quartz crystal microbalance (EQCM) and probe beam deflection (PBD). J Phys Chem B 103 8899-8907 Henderson MJ, French H, Hillman AR, Vieil E (1999) A combined EQCM and probe beam defection study of salicylate ion transfer at a polypyrrole modified electrode. Electrochem Solid State Lett 2(12) 631-633... 

The concentration gradient of species moving either toward the electrode or into the solution can be measured with the probe beam deflection (PBD also called the Mirage effect) technique [100-104]. A light beam (in practically all reported cases,... 

Refractive index changes in a quiescent electrolyte produced by an electrochemical reaction at a working elec-trode/solution interface can be detected either interfero-metrically [123] or by probe beam deflection (PBD) [148]. The mirage deflection is due to both a tempera-... 

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