IRRAS accessories

An error in the photometric measurements of 0.005 [456] corresponds to an accuracy of 0.01 for AR/R for a single reflection. Since the quantity being measured is the ratio R/Ro, he error introduced by radiation loss from the IRRAS accessory and reflection from the sample is partially corrected. 

Figure 4.10. Scheme of single-reflection IRRAS accessory with horizontal sample (1) directing mirrors (2) sample (3) sample holder. Reprinted, by permission, from J. Chatelet, H. H. Claasen, D. M. Gruen, I. Sheft, and R. B. Wright,App/. Spectrosc. 29,185 (1975), p. 187, Fig. 1. Copyright 1975 Society for Applied Spectroscopy.

Fig. 11. (A) Design of the Langmuir trough used in the current studies. The trough is shuttled under computer control for IR illumination of the background surface and monolayer covered surface. (B) Schematic of the IRRAS instrument displaying the sections of the accessory that rotate in concert under computer control to provide the desired angle of incidence. Taken from Ref. [81] with permission from American Chemical Society.

Figure 4.7. (a) Accessory and (b) modification of opticai scheme for recording spectra by muitipie metaiiic iRRAS (1,2) guiding mirrors (3) sampies (4) siiicon piate insert, (a) Reprinted, by permission, from V. P. Toistoy, G. N. Kuznetsova, M. i. ivanova, and A. I. Somsikov, Pribory i tekhnika experimenta, No. 3, 220-221 (1982) p. 220, Fig. 1. Copyright 1982 Pribory i tekhnika experimenta p) Reprinted, by permission, from V. P. Toistoy, in V. B. Aieskovski (Ed.), Precision Synthesis of Solids, Voi. 2, Leningrad State University Press, Leningrad, 1987, p. 76 p. 88, Fig. 13. Copyright 1987 St. Petersburg University Press.

As in the case for IRRAS, ATR spectra require special accessories that are mounted in the sample compartment of a serial spectrometer. Central to all ATR... 

Figure 4.53. In situ IRRAS spectra of SCN adsorbed on Cu electrode (a) PM and p) ordinary SPAIRS spectra. Reference is—1.2 V (Ag-AgCI)and sample potentials are marked. Experiments were performed on Mattson RS-1 spectrometer configured with external bench analogous to that shown in Fig. 4.51. Photoelastic modulator was Flinds International ZnSe Series II modulator, operating at 37 kFIz. The PM wavefront was sampled in real time with ATI Instruments real-time sampling accessory. The MCT detector with D of 5 x 10 ° cm W was used. Spectra are represented in absorption depth of PM signal (Aflpm). Reprinted, by permission, from W. N. Richmond, P. W. Faguy, R. S. Jackson, and S. C. Weibel, Anal. Chem 68, 621 (1996), p. 625. Copyright 1996 American Chemical Society.

The high sensitivity of IRRAS allowed the composition of natural protective films caused by polishing surfaces of Al, Mg, and Cu to be investigated [293], Prior to recording the spectra, the ground metallic plates were polished with diamond or Cr203 paste. In the latter case, alcohol or water was used as a solvent. The flatness and the quality of the final surface were never worse than 3 p.m and VI2, respectively. The spectra were recorded by IRRAS in p-polarized radiation on a UR-20 spectrophotometer with a specially developed accessory shown in Fig. 4.7. A polarizer was mounted in front of the entrance slit. The size of the metallic samples was 20 x 92 mm, and the number of reflections N = 26. 

---