Fast and Ultrafast Time‐Resolved Mid‐Infrared Spectrometry Using Lasers

Grills, David C.; George, Michael W.

doi:10.1002/0470027320.s0219

Cited by 7 publications

(6 citation statements)

References 139 publications

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“…sampling more than 100 cm −1 at once) and multi-channel detection. In parallel, signal-to-noise ratio has been improved by higher photon flux lasers and superior time resolution has been made possible by shorter laser pulse times (Grills & George 2002). In addition to studies of CO photolysis from proteins, lighttriggered time-resolved IR methods have been applied to a range of small-molecule systems including transition metal carbonyl complexes (Butler et al 2007) and photodamaged DNA bases (Kuimova et al 2006).…”

Section: Recent Developments In Infrared Instrumentation and Methodolmentioning

confidence: 99%

Triggered infrared spectroscopy for investigating metalloprotein chemistry

Vincent

2010

Phil. Trans. R. Soc. A.

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Recent developments in infrared (IR) spectroscopic time resolution, sensitivity and sample manipulation make this technique a powerful addition to the suite of complementary approaches for the study of time-resolved chemistry at metal centres within proteins. Application of IR spectroscopy to proteins has often targeted the amide bands as probes for gross structural change. This article focuses on the possibilities arising from recent IR technical developments for studies that monitor localized vibrational oscillators in proteins-native or exogenous ligands such as NO, CO, SCN − or CN − , or genetically or chemically introduced probes with IR-active vibrations. These report on the electronic and coordination state of metals, the kinetics, intermediates and reaction pathways of ligand release, hydrogen-bonding interactions between the protein and IR probe, and the electrostatic character of sites in a protein. Metalloprotein reactions can be triggered by light/dark transitions, an electrochemical step, a change in solute composition or equilibration with a new gas atmosphere, and spectra can be obtained over a range of time domains as far as the sub-picosecond level. We can expect to see IR spectroscopy exploited, alongside other spectroscopies, and crystallography, to elucidate reactions of a wide range of metalloprotein chemistry with relevance to cell metabolism, health and energy catalysis.

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Section: Recent Developments In Infrared Instrumentation and Methodolmentioning

confidence: 99%

Triggered infrared spectroscopy for investigating metalloprotein chemistry

Vincent

2010

Phil. Trans. R. Soc. A.

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“…23 However, such a source does not provide sufficient intensity in the mid-IR portion of the spectrum. Traditionally, continuous wave (CW) mid-IR sources for nano-to millisecond TRIR spectroscopy have been limited to either globars 26,27 and tunable lead-salt diode lasers, 28 both of which require the use of a monochromator to select a single probe wavelength, or line-tunable CO or CO 2 gas lasers 28,29 (see Table I for a list of the advantages and disadvantages of these sources for use with pulse radiolysis). Each of these has proved to be extremely useful in different forms of TRIR spectroscopy when coupled with laser flash photolysis.…”

Section: B Quantum Cascade Lasers As An Ir Probe Sourcementioning

confidence: 99%

Development of nanosecond time-resolved infrared detection at the LEAF pulse radiolysis facility

Grills

Farrington

Layne

et al. 2015

Review of Scientific Instruments

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When coupled with transient absorption spectroscopy, pulse radiolysis, which utilizes high-energy electron pulses from an accelerator, is a powerful tool for investigating the kinetics and thermodynamics of a wide range of radiation-induced redox and electron transfer processes. The majority of these investigations detect transient species in the UV, visible, or near-IR spectral regions. Unfortunately, the often-broad and featureless absorption bands in these regions can make the definitive identification of intermediates difficult. Time-resolved vibrational spectroscopy would offer much improved structural characterization, but has received only limited application in pulse radiolysis. In this paper, we describe in detail the development of a unique nanosecond time-resolved infrared (TRIR) detection capability for condensed-phase pulse radiolysis on a new beam line at the LEAF facility of Brookhaven National Laboratory. The system makes use of a suite of high-power, continuous wave external-cavity quantum cascade lasers as the IR probe source, with coverage from 2330 to 1051 cm(-1). The response time of the TRIR detection setup is ∼40 ns, with a typical sensitivity of ∼100 μOD after 4-8 signal averages using a dual-beam probe/reference normalization detection scheme. This new detection method has enabled mechanistic investigations of a range of radiation-induced chemical processes, some of which are highlighted here.

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“…However, absorption bands in these regions (particularly in the UV and visible) are often broad and difficult to assign to specific structures of reaction intermediates that would aid in mechanistic interpretation. Time-resolved vibrational spectroscopy (TRVS), with either mid-IR absorption or resonance Raman detection, [6][7][8] is a particularly powerful approach since in contrast to the majority of UV/visible measurements, it can provide rich structural information on transient species through the appearance of narrow, highly characteristic spectral bands. Thus, time-resolved infrared (TRIR) and time-resolved resonance Raman (TR 3 ) spectroscopy have become widely used techniques for the identification of short-lived intermediates generated by pulsed laser excitation.…”

Section: Introductionmentioning

confidence: 99%

Application of External-Cavity Quantum Cascade Infrared Lasers to Nanosecond Time-Resolved Infrared Spectroscopy of Condensed-Phase Samples following Pulse Radiolysis

et al. 2010

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Pulse radiolysis, utilizing short pulses of high-energy electrons from accelerators, is a powerful method for rapidly generating reduced or oxidized species and other free radicals in solution. Combined with fast time-resolved spectroscopic detection (typically in the ultraviolet/visible/near-infrared), it is invaluable for monitoring the reactivity of species subjected to radiolysis on timescales ranging from picoseconds to seconds. However, it is often difficult to identify the transient intermediates definitively due to a lack of structural information in the spectral bands. Time-resolved vibrational spectroscopy offers the structural specificity necessary for mechanistic investigations but has received only limited application in pulse radiolysis experiments. For example, time-resolved infrared (TRIR) spectroscopy has only been applied to a handful of gas-phase studies, limited mainly by several technical challenges. We have exploited recent developments in commercial external-cavity quantum cascade laser (EC-QCL) technology to construct a nanosecond TRIR apparatus that has allowed, for the first time, TRIR spectra to be recorded following pulse radiolysis of condensed-phase samples. Near single-shot sensitivity of DeltaOD <1 x 10(-3) has been achieved, with a response time of <20 ns. Using two continuous-wave EC-QCLs, the current apparatus covers a probe region from 1890-2084 cm(-1), and TRIR spectra are acquired on a point-by-point basis by recording transient absorption decay traces at specific IR wavelengths and combining these to generate spectral time slices. The utility of the apparatus has been demonstrated by monitoring the formation and decay of the one-electron reduced form of the CO(2) reduction catalyst, [Re(I)(bpy)(CO)(3)(CH(3)CN)](+), in acetonitrile with nanosecond time resolution following pulse radiolysis. Characteristic red-shifting of the nu(CO) IR bands confirmed that one-electron reduction of the complex took place. The availability of TRIR detection with high sensitivity opens up a wide range of mechanistic pulse radiolysis investigations that were previously difficult or impossible to perform with transient UV/visible detection.

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Fast and Ultrafast Time‐Resolved Mid‐Infrared Spectrometry Using Lasers

Abstract: The sections in this article are Introduction Fast TRIR Spectroscopy Fast TRIR Spectroscopy Using IR Lasers CW CO Lasers … Show more

Cited by 7 publications

References 139 publications

Triggered infrared spectroscopy for investigating metalloprotein chemistry

Triggered infrared spectroscopy for investigating metalloprotein chemistry

Development of nanosecond time-resolved infrared detection at the LEAF pulse radiolysis facility

Application of External-Cavity Quantum Cascade Infrared Lasers to Nanosecond Time-Resolved Infrared Spectroscopy of Condensed-Phase Samples following Pulse Radiolysis

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