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Title: Vibrational dynamics of aqueous hydroxide solutions probed using broadband 2DIR spectroscopy

We employed ultrafast transient absorption and broadband 2DIR spectroscopy to study the vibrational dynamics of aqueous hydroxide solutions by exciting the O–H stretch vibrations of the strongly hydrogen-bonded hydroxide solvation shell water and probing the continuum absorption of the solvated ion between 1500 and 3800 cm -1. We observe rapid vibrational relaxation processes on 150–250 fs time scales across the entire probed spectral region as well as slower vibrational dynamics on 1–2 ps time scales. Furthermore, the O–H stretch excitation loses its frequency memory in 180 fs, and vibrational energy exchange between bulk-like water vibrations and hydroxide-associated water vibrations occurs in ~200 fs. The fast dynamics in this system originate in strong nonlinear coupling between intra- and intermolecular vibrations and are explained in terms of non-adiabatic vibrational relaxation. These measurements indicate that the vibrational dynamics of the aqueous hydroxide complex are faster than the time scales reported for long-range transport of protons in aqueous hydroxide solutions.
Authors:
 [1] ;  [2]
  1. Univ. of Chicago, IL (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. Univ. of Chicago, IL (United States)
Publication Date:
Grant/Contract Number:
SC0011456; SC0014305
Type:
Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 143; Journal Issue: 19; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of Chicago, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1469646
Alternate Identifier(s):
OSTI ID: 1226104

Mandal, Aritra, and Tokmakoff, Andrei. Vibrational dynamics of aqueous hydroxide solutions probed using broadband 2DIR spectroscopy. United States: N. p., Web. doi:10.1063/1.4935174.
Mandal, Aritra, & Tokmakoff, Andrei. Vibrational dynamics of aqueous hydroxide solutions probed using broadband 2DIR spectroscopy. United States. doi:10.1063/1.4935174.
Mandal, Aritra, and Tokmakoff, Andrei. 2015. "Vibrational dynamics of aqueous hydroxide solutions probed using broadband 2DIR spectroscopy". United States. doi:10.1063/1.4935174. https://www.osti.gov/servlets/purl/1469646.
@article{osti_1469646,
title = {Vibrational dynamics of aqueous hydroxide solutions probed using broadband 2DIR spectroscopy},
author = {Mandal, Aritra and Tokmakoff, Andrei},
abstractNote = {We employed ultrafast transient absorption and broadband 2DIR spectroscopy to study the vibrational dynamics of aqueous hydroxide solutions by exciting the O–H stretch vibrations of the strongly hydrogen-bonded hydroxide solvation shell water and probing the continuum absorption of the solvated ion between 1500 and 3800 cm-1. We observe rapid vibrational relaxation processes on 150–250 fs time scales across the entire probed spectral region as well as slower vibrational dynamics on 1–2 ps time scales. Furthermore, the O–H stretch excitation loses its frequency memory in 180 fs, and vibrational energy exchange between bulk-like water vibrations and hydroxide-associated water vibrations occurs in ~200 fs. The fast dynamics in this system originate in strong nonlinear coupling between intra- and intermolecular vibrations and are explained in terms of non-adiabatic vibrational relaxation. These measurements indicate that the vibrational dynamics of the aqueous hydroxide complex are faster than the time scales reported for long-range transport of protons in aqueous hydroxide solutions.},
doi = {10.1063/1.4935174},
journal = {Journal of Chemical Physics},
number = 19,
volume = 143,
place = {United States},
year = {2015},
month = {11}
}