Absorption spectroscopy, in chemical

Figure 4.3 Reprinted from Wear, Vol. 202, Z. Yin, M. Kasrai, M. Fuller, G.M. Bancroft, K. Fyfe and K.H. Tan, Application of soft X-ray absorption spectroscopy in chemical characterization of anti wear films generated by ZDDP the effect of physical parameters, Part I, pp. 172-191. Copyright 1997, with permission from Elsevier.

USES OF HIGH-SENSITIVITY WHITE-LIGHT ABSORPTION SPECTROSCOPY IN CHEMICAL VAPOR DEPOSITION AND PLASMA PROCESSING... 

Uses of High-Sensitivity White-Light Absorption Spectroscopy in Chemical Vapor Deposition and Plasma Processing,... 

J. Pritchard, Reflection-absorption infrared spectroscopy, in Chemical Physics of Solids and Their Surfaces, Eds M. W. Roberts and J. M. Thomas, Chemical Society, London, 1978, Vol. 7, p. 157. 

Metals can be conveniently determined by emission spectroscopy using inductively coupled plasma (ICP). A great advantage of ICP emission spectroscopy as applied to environmental analysis is that several metals can be determined simultaneously by this method. Thus, multielement analysis of unknown samples can be performed rapidly by this technique. Another advantage is that, unlike atomic absorption spectroscopy, the chemical interference in this method is very low. Chemical interferences are generally attributed to the formation of molecular compounds (from the atoms) as well as to ionization and thermochemical effects. The principle of the ICP method is described below. 

Valuable information on the physical-chemical properties of radicals can be often obtained by photoelectron studies in which the electron is detached, so that open-shell systems can be created. Moreover, excited electronic states of radicals can be studied by absorption spectroscopy in the UV-vis regions. An analysis of the resulting experimental spectra can be even more difficult than for ground-state IR or Raman ones. The additional factors can be related to the often not trivial identification of electronic band origin, possible overlap of several electronic transitions and nonadia-batic effects. Although such complications are challenging also for the theoretical approaches, some examples show already their interpretative efficiency. 

Golden WG (1985) Fourier Transform Infrared Reflection-Absorption Spectroscopy. In Ferraro J R, Basile LJ (eds) Fourier Transform Infrared Spectroscopy, Applications to Chemical Systems, vol 4, Academic, Orlando, pp 315 - 344 Golden WG, Dunn DS, Overend J (1981) J Catalysis 71 395 Goldman A, Saunders RS (1979) J Quant Spectrosc Rad Transfer 21 155... 

The properties of the transmission Raman geometry are well suited to the requirements of pharmaceutical production lines, thus underlining the potential of this method to displace existing NIR absorption spectroscopy in applications where a higher chemical specificity is required. However, further studies are required to establish the technique s sensitivity limits and to validate its potential. 

Chemical interference effects in atomic fluorescence are similar to those observed in atomic absorption spectroscopy. In addition, any process that affects the quantum efficiency of the fluorescence or disrupts normal emission of the energy of the excited state also can be considered as a chemical interference. 

Ndou TT and Warner IM (1991) Multidimensional luminescence and absorption spectroscopy in analytical chemistry. Chemical Reviews 91 493-507. 

The task of X-ray spectroscopy in clarifying the atomic structure of the elements was for the most part accomplished in the mid-thirties. Since then its even more voluminous task has been to trace modifications of the atomic shell configurations and of their energetics by the chemical bonding in molecules and solids. In absorption spectroscopy these chemical effects can be detected by chemical shifts and by new fine structures in the absorption line or edge and in the near edge region (E — < 30 eV). The existence of such chemical effects has been known since the... 

W. G. Golden, Fourier transform infrared reflection-absorption spectroscopy, in Fourier Transform Infrared Spectroscopy Applications to Chemical Systems, J. R. Ferraro and L. J. Basile, Eds., Academic Press, Orlando, IL, 1985, Vol. 4, p. 315. 

Fuller, M.L.S., Kasrai, M., and Bancroft, G.M. (2002) Application of X-ray absorption spectroscopy in tribology, in Chemical Applications of Synchrotron Radiation... 

The conditions which determine whether flash photolysis can be used to smdy a given chemical system are (i) a precursor of the species of kinetic interest has to absorb light (normally from a pulsed laser) (ii) this species is produced on a timescale that is short relative to its lifetime in the system. Current technical developments make it easy to study timescales of nanoseconds for production and analysis of species, and the use of instrumentation with time resolution of picoseconds is already fairly common. In certain specific cases, as we will see in the last part of this chapter, it is possible to study processes on timescales greater than a few femtoseconds. Once the species of interest has been produced, it is necessary to use an appropriate rapid detection method. The most common technique involves transient optical absorption spectroscopy. In addition, luminescence has been frequently used to detect transients, and other methods such as time-resolved resonance Raman spectroscopy and electrical conductivity have provided valuable information in certain cases. 

UV-vis refers to absorption spectroscopy in the ultraviolet-visible spectral region. The absorption in the visible range directly affects the perceived color of the chemicals involved. The UV-vis spectra are measured using spin casted films, or dilute polymer solutions. Films are more representative for the active layer behavior in SCs, while solutions are more reliable when comparing the different polymers or blends. For example, the film deposited on ITO substrate may be dissolved in a suitable solvent (e.g., in chloroform at concentration of 25 pg/mL, in 10 mm quartz cell) and either directly used in a spectrometer, or spin casted on glass slides, vacuum dried and measured at the wavelength 280 to 900 nm at a rate of 300 nm/min.i ... 

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