Pressure-tuning spectroscopy

Drickamer H G 1990 Forty years of pressure tuning spectroscopy Ann. Rev. Mater. Sc/. 20 1... 

UV, Photoelectron, Pressure Tuning Spectroscopy, and Laser Flash Photolysis 395... 

The volume of activation (AV ) can also be measured by changing the overall pressure of the reaction vessel. This can be accomplished using a technique known as pressure-tuning spectroscopy (PTS) or by other methods. The relationship between the rate constant as a function of pressure and A is shown in Equation (17.9), which is simply a modification ofthevan t Hoff equation. If AV is independent of the pressure. Equation (17.9) can be integrated at constant T to yield Equation (17.10). The volume of activation can then be determined from the slope of the line when ln(k) is plotted versus the pressure. 

Pressure Tuning Fourier Transform Infrared and Raman Spectroscopy of Anionic Surfactants... 

In this report we describe novel pressure tuning vibrational spectroscopic techniques that can be used to study aqueous surfactant solutions and discuss in some detail two examples of such studies with micellar solutions of anionic surfactants, one using Fourier transform infrared (FT-IR) and another using Raman spectroscopy. 

Fig. 15. Pressure tuning hole burning spectroscopy of protoporphyrin IX in a glass, (a) Absorption spectrum. The arrow indicates the frequency where the pressure shift vanishes. The corresponding hole is shown in the inset, (b) Shifts and broadening AT of the hole with pressure as a function of burn frequency [From J. Gafert, J. Friedrich, and F. Parak, J. Chem. Phys. 99, 2478 (1993)].

Fig. 18. Pressure tuning hole burning spectroscopy of mesoporphyrin IX-substituted horseradish peroxidase, (a) Spectrum of the enzyme complexed with a substrate molecule, namely, naphthohydroxamic acid. Inset shows the arrangement of the prosthetic group, the substrate molecule, and some amino acids, (b) Spectrum of the free enzyme. Inset shows the behavior of a hole under pressure cycles (0-2 MPa). Several traces are superimposed. Note the full reversibility [From J. Fidy, J. M. Vanderkooi, J. Zollfrank, and J. Friedrich, Biophys. J. 63, 1605 (1992)].

Raman spectroscopy continues to be an extremely useful probe for examining the structural features of diiodine [14, 15, 23] and interhalogen [24] thioamide compounds. In the pressure-tuning FT-Raman spectroscopic work reported here, structural phase transitions were detected for compounds 1, 4, and 5 at 35, 25, and 32 kbar, respectively. There was no evidence of any free I formation for any of the compounds examined under high pressures. The similarity of the FT-Raman spectra of the two pairs of compounds, 1, 2, 3, and 4, may be the result of them being closely related perturbed diiodine complexes [25]. In the case of compounds 3 and 4, it is also possible that a pressure-induced disproportionation of 3 may have occurred leading to the formation of 4, in a similar manner to the effect of pressure on [(bztzdtH) 12 (bztzdtH = benzothiazole-2-thione) [4]. Finally, the FT-Raman data show that 5 is best formulated as (thpm) ) rather than the ionic species [(thpm)IJ [l3] -... 

K. Goossens, L. Smeller, J. Erank, and K. Heremans, Eur. J. Biochem., 236, 254 (1996). Pressure-Tuning the Conformation of Bovine Pancreatic Trypsin Inhibitor Studied by Eourier-Transform Infrared Spectroscopy. 

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