Raman thermometry

Eckbreth, A. C. "Laser Raman Thermometry Experiments in Simulated Combustor Environments" AIAA Paper No. 76-27, 1976. 

A knowledge of the electrolyte temperature is important in CE as temperature changes in the electrolyte influence precision, accuracy, separation efficiency, and method robustness [7,14,32], During the past two decades, a considerable amount of research has been conducted toward electrolyte temperature measurements in CE [1,14,19,21,32 2], Early methods have included using the variation of electroosmotic mobility (eieof), electrophoretic mobility (p-ep), and electrical conductivity (k) to measure temperature [38,39], More recently, techniques such as external thermocouples [21], Raman thermometry [19,40], NMR spectroscopy [32,35], thermochromic probes [41], and the variation in fluorescence response [42] have been used to measure temperatures. Most of these methods require the modiflcation of the existing instrument and/or the purchase of additional equipment. 

Smith JD, Cappa CD, Diisdell WS, Cohen RC, Saykally RJ (2006) Raman thermometry measurements of free evaporation fi om liquid water droplets. J Am Chem Soc 128 (39) 12892-12898... 

Morris and Shaver [11] used the water Raman spectrum to perform Raman thermometry in solutions of sodium benzoate. The relative intensities of (water) bands in the OH stretching envelope are strongly temperature dependent (Fig. 2). An Arrhenius plot can be based on band areas measured in the intervals 3100-3350 cm and 3350-3600 cm Because the water stretching envelope is broad, the measurements should be successful with low-resolution (20-30 cm ) instruments, although they were performed on an instrument with 8-cm resolution. After calibration against a thermometer or thermocouple, the student monitors the cooling of a solution at 2-min intervals over a period of 30 min. 

Smith, J.D., Cappa, C.D., Drisdell, W.S., Cohen, R.C., Saykally, R.J. Raman thermometry measurements of free evaporation from liquid water droplets. J. Am. Chem. Soc. 128,... 

This comprehensive review of theoretical models and techniques will be invaluable to theorists and experimentalists in the fields of infrared and Raman spectroscopy, nuclear magnetic resonance, electron spin resonance and flame thermometry. It will also be useful to graduate students of molecular dynamics and spectroscopy. 

Droplet temperature is of interest in practical spray processes since it influences the associated heat and mass transfer, chemical reactions, and phase changes such as evaporation or solidification. Various forms of Rayleigh, Raman and fluorescence spectroscopies have been developed for measurements of droplet temperature and species concentration in sprays.16471 Rainbow refractometry (thermometry), polarization ratioing thermometry, and exciplex method are some examples of the droplet temperature measurement techniques. 

In exemplarily flame measurements conducted at the LTT-Erlangen (Will et al., 1996), flame temperatures were determined by emission spectroscopy or coherent anti-Stokes Raman scattering (CARS) thermometry depending on the maximum soot concentration. Typical temperatures are in the range of 1800 K in the middle of the flames and up to 2100 K in the outer regions where the reactions take place. A typical measurement setup for two-dimensional LII investigations is shown in Figure 10. 

Two techniques, which appear well suited to the diagnostic probing of practical flames with good spatial and temporal resolution, are coherent anti-Stokes Raman spectroscopy (CARS) and saturated laser fluorescence. The two techniques are complementary in regard to their measurement capabilities. CARS appears most appropriate for thermometry and major species concentration measurements, saturated laser fluorescence to trace radical concentrations. With electronic resonant enhancement (6), CARS may be potentially useful for the latter as well. Fluorescence thermometry is also possible (7, 8) but generally, is more tedious to use than CARS. In this paper, recent research investi-... 

Herzberg et al. showed with the help of Coherent anti-Stokes Raman scattering (CARS) thermometry that heating at a rate of 1700 K/s causes a delay between the temperature of the gaseous phase and the tube wall of at several hundred milliseconds (Figure 6.23) [90]. However, in the first 200 to 300 ms of the atomization phase, the delay is minimal, and just beyond 300 ms a usually proportional delay is determined. 

Coherent Anti-Stokes Raman Scattering (CARS) Thermometry is a technique for temperature measurement in high temperature environments using a third-order nonlinear optical process involving a pump and a Stokes frequency laser beam that interacts with the sample and generates a coherent anti-Stokes frequency beam. 

Another noncontact technique for measuring high temperatures involves Raman spectroscopy, in particular the nonlinear process known as coherent anti-Stokes Raman spectroscopy (CARS) (Radiation Thermometry, 1982). This technique is finding practical applications in measurements of temperatures of flames (in internal combustion engines, in jet engines) and of hot gases. The imprecision of such temperature measurements is generally a few percent. 

The main trouble with SpRS thermometry is associated with the small Raman cross section. This fact is partly counterbalanced by choosing the SpRS spectrum of the most abundant and stable species. Usually, nitrogen is the best candidate in air-fed combustion realized in laboratory burners [7,9] and the choice proves to be valid even for industrial flames and furnaces [18-20], but this is not enough to make SpRS thermometry evolve into a common resource. For instance, the RS cross section is about three orders of magnitude greater and two-dimensional thermometry is dominated by RS instead of the more accurate SpRS. 

Kataoka, H., Maeda, S., Hirose, C., and Kajiyama, K. "A Study for N2 Coherent Anti-Stokes Raman Spectroscopy Thermometry at High Pressure." Applied Spectroscopy 37, no. 6 (1983) 508-12. 

Greenhalgh, D. A., and Rorter, F. M. "The Application of Coherent Anti-Stokes Raman Scattering to Turbulent Combustion Thermometry." Combustion and Flame 49 (1983) 171-81. 

Vestin, R, Sedarsky, D., Collin, R., Alden, M., Linne, M., and Bengtsson, R. "Rotational Coherent Anti-Stokes Raman Spectroscopy (CARS) Applied to Thermometry in High Rressure Flames." Combustion and Flame 154 (2008) 143. 

Kaminski, C. R, and Ewart, P. "Multiples H2 Coherent Anti-Stokes Raman Scattering Thermometry with a Modeless Dye Laser." Applied Optics 38 (1997) 731. 

D. V. Murphy and R. K. Chang, Single-Pulse Broadband Rotational Coherent Antl-Stokes Raman-Scatterlng Thermometry of Cold N2 Gas, Opt. Lett. 6 233 (1981). 

One application of rovibrational spectroscopy is molecular thermometry. This type of thermometry is a well-known diagnostic tool and used, for example, in combustion studies, where the rotational and vibrational temperatures are measured, often with coherent Raman spectroscopy, in order to determine their temperature or that of the surrounding medium. 

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