Time resolved resonance Raman

The Fe-N mode is at 222 in the R state and 207 cnY in the T state for the a subunits, but only shifted to 218 T state for the (3 subunits. This is consistent with the interpretation that the Fe-imidazole interations are weakened more in the T state of the a subunits than p subunits. Time-resolved resonance Raman studies have shown that the R T switch is complete on a 10 ps tuuescale [38]. Finally, UV excitation of the aromatic protein side chains yields... [Pg.1172]

Time-resolved spectroscopy has become an important field from x-rays to the far-IR. Both IR and Raman spectroscopies have been adapted to time-resolved studies. There have been a large number of studies using time-resolved Raman [39], time-resolved resonance Raman [7] and higher order two-dimensional Raman spectroscopy (which can provide coupling infonuation analogous to two-dimensional NMR studies) [40]. Time-resolved IR has probed neutrals and ions in solution [41, 42], gas phase kmetics [42] and vibrational dynamics of molecules chemisorbed and physisorbed to surfaces [44]- Since vibrational frequencies are very sensitive to the chemical enviromnent, pump-probe studies with IR probe pulses allow stmctiiral changes to... [Pg.1172]

Bell S E J 1996 Time-resolved resonance Raman spectroscopy A/ a/ysf 121 R107-20... [Pg.1175]

Kincaid J R 1995 Structure and dynamics of transient species using time-resolved resonance Raman-spectroscopy Biochemical Spectroscopy Methods Enzymol. vol 246, ed K Sauer (San Diego, CA Academic) pp 460-501... [Pg.1175]

Tripathi G N R and Schuler R H 1982 Time-resolved resonance Raman scattering of transient radicals the p-aminophenoxyl radical J. Chem. Phys. 76 4289-90... [Pg.1227]

Figure C3.1.11. Apparatus for pump-probe time-resolved resonance Raman spectroscopy. (From Varotsis C and Babcock G T 1993 K4ethods Enzymol. 226 409-31.)...

Friedman J M 1994 Time-resolved resonance Raman spectroscopy as probe of structure, dynamics, and reactivity in hemoglobin Methods Enzymol. 232 205-31... [Pg.2970]

An Introduction to Time-Resolved Resonance Raman Spectroscopy and Its Application to Reactive Intermediates... [Pg.123]

Typical Instrumentation and Methods for Doing Time-Resolved Resonance Raman (TR ) Experiments... [Pg.123]

AN INTRODUCTION TO TIME-RESOLVED RESONANCE RAMAN SPECTROSCOPY... [Pg.124]

Time-resolved resonance Raman (TR ) spectroscopy experiments were first reported in 1976 and used a 30 ns pulse radiolytic source to generate the intermediates that were then probed on the microsecond time-scale by a laser source to generate the TR spectrum. TR spectroscopy was then extended to study intermediates... [Pg.124]

TYPICAL INSTRUMENTATION AND METHODS FOR DOING TIME-RESOLVED RESONANCE RAMAN (TR ) EXPERIMENTS... [Pg.129]

Since there are a large number of different experimental laser and detection systems that can be used for time-resolved resonance Raman experiments, we shall only focus our attention here on two common types of methods that are typically used to investigate chemical reactions. We shall first describe typical nanosecond TR spectroscopy instrumentation that can obtain spectra of intermediates from several nanoseconds to millisecond time scales by employing electronic control of the pnmp and probe laser systems to vary the time-delay between the pnmp and probe pnlses. We then describe typical ultrafast TR spectroscopy instrumentation that can be used to examine intermediates from the picosecond to several nanosecond time scales by controlling the optical path length difference between the pump and probe laser pulses. In some reaction systems, it is useful to utilize both types of laser systems to study the chemical reaction and intermediates of interest from the picosecond to the microsecond or millisecond time-scales. [Pg.129]

Ultrafast time-resolved resonance Raman (TR ) spectroscopy experiments need to consider the relationship of the laser pulse bandwidth to its temporal pulse width since the bandwidth of the laser should not be broader than the bandwidth of the Raman bands of interest. The change in energy versus the change in time Heisenberg uncertainty principle relationship can be applied to ultrafast laser pulses and the relationship between the spectral and temporal widths of ultrafast transform-limited Gaussian laser pulse can be expressed as... [Pg.132]

SOME APPLICATIONS OF TIME-RESOLVED RESONANCE RAMAN (TR3) SPECTROSCOPY TO STUDY SELECTED CHEMICAL REACTIONS AND THEIR REACTIVE INTERMEDIATES... [Pg.145]

In this section, we will very briefly describe selected examples of the application of time-resolved resonance Raman (TR ) spectroscopy to the study of chemical reactions and the reactive intermediates which participate in those transformations. [Pg.145]

Figure 3.14. Picosecond Kerr gated time-resolved resonance Raman (ps-K-TR ) spectra of the ICT state of DMABN (a), DMABN-N (b) and DMABN-dg (c) obtained by 267 nm pnmp, 330nm probe in methanol at 50ps delay time. (Reprinted with permission from reference [28]. Copyright (2001) American Chemical Society.)...

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