The hydration structure of aqueous carbonic acid from X-ray absorption spectroscopy

Despite much effort, aqueous carbonic acid (H2CO3) remains poorly characterized because it is very short-lived. We describe the detection and characterization of aqueous H2CO3 by X-ray absorption spectroscopy, wherein protonation of a bicarbonate solution continuously generates the acid under ambien...

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Bibliographic Details
Published in:Chemical Physics Letters
Main Authors: Lam, Royce K, England, Alice H, Sheardy, Alex T, Shih, Orion, Smith, Jacob W, Rizzuto, Anthony M, Prendergast, David, Saykally, Richard J
Format: Article in Journal/Newspaper
Language:unknown
Published: eScholarship, University of California 2014
Subjects:
Physical Sciences
Chemical Sciences
Technology
Chemical Physics
Carbonic acid
Online Access:https://escholarship.org/uc/item/8km10634
https://escholarship.org/content/qt8km10634/qt8km10634.pdf
https://doi.org/10.1016/j.cplett.2014.09.052
Description
Summary:Despite much effort, aqueous carbonic acid (H2CO3) remains poorly characterized because it is very short-lived. We describe the detection and characterization of aqueous H2CO3 by X-ray absorption spectroscopy, wherein protonation of a bicarbonate solution continuously generates the acid under ambient conditions. Accompanying first principles calculations of the carbon K-edge transitions facilitate spectral assignment and interpretation in terms of the H2CO3 π∗ orbital, which exhibits a small (0.2 eV), systematic blueshift relative to that of bicarbonate. These results establish the detailed hydration properties of this short-lived molecule and will thereby facilitate future studies of carbonate chemistry in biological and geological system.

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