Mid-Infrared Time-Resolved Frequency Comb Spectroscopy of Transient Free Radicals
Abstract
We demonstrate time-resolved frequency comb spectroscopy (TRFCS), a new broadband absorption spectroscopy technique for the study of trace free radicals on the microsecond timescale. We apply TRFCS to study the time-resolved, mid-infrared absorption of the deuterated hydroxyformyl radical trans-DOCO, an important short-lived intermediate along the OD + CO reaction path. Directly after photolysis of the chemical precursor acrylic acid-d_1, we measure absolute trans-DOCO product concentrations with a sensitivity of 5 × 10^(10) cm^(–3) and observe its subsequent loss with a time resolution of 25 μs. The multiplexed nature of TRFCS allows us to detect simultaneously the time-dependent concentration of several other photoproducts and thus unravel primary and secondary chemical reaction pathways.
Additional Information
© 2014 American Chemical Society. Received: April 30, 2014. Accepted: June 10, 2014. Publication Date (Web): June 10, 2014. We thank Keeyoon Sung of the National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) for providing a list of D_2O mid-IR line positions and intensities measured by Robert A. Toth of JPL. We are grateful to Scott A. Diddams of the National Institute of Standards and Technology (NIST) and Tim Dinneen of Precision Photonics for providing the mid-IR VIPA etalon used in this work. We also thank Brad Baxley for artistic contributions to Figure 1 and acknowledge financial support from NIST, NSF, NASA, AFOSR, and DTRA. Adam J. Fleisher was supported by a National Research Council postdoctoral fellowship and Thinh Bui by a NASA Earth and Space Science Fellowship.Attached Files
Supplemental Material - jz5008559_si_001.pdf
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Additional details
- Eprint ID
- 48632
- DOI
- 10.1021/jz5008559
- Resolver ID
- CaltechAUTHORS:20140815-145924440
- National Institute of Standards and Technology (NIST)
- NSF
- NASA
- Air Force Office of Scientific Research (AFOSR)
- Defense Threat Reduction Agency (DTRA)
- National Research Council of Canada
- Created
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2014-08-15Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field