Terahertz spectroscopy of aqueous ionic solutions to understand the role of hydrogen-bond network breaking and strengthening in the Hofmeister
Lead Research Organisation:
University of Strathclyde
Department Name: Physics
Abstract
In 1888, Franz Hofmeister in his paper 'Zur Lehre von der Wirkung der Salze' discovered a series of salts -- later named the Hofmeister series -- that have an increasing propensity to precipitate proteins. It became clear over time that the Hofmeister series is related to the propensity of various ions to solvate water. The classical view is that ions may be classed as kosmotropes or chaotropes: kosmotropes are thought to induce a more icelike ordering in the surrounding water whereas chaotropes disrupt the local tetrahedral network. However, this tidy picture was thrown into disarray by ultrafast infrared studies pertaining to show that the water structure remains unaltered beyond the first solvation shell around solvated ions (the 'solventberg' model). Here we propose to use terahertz Raman and infrared spectroscopy combined with time-resolved two-dimensional infrared spectroscopy (in collaboration with Robin Hochstrasser) to study femtosecond hydrogen-bond dynamics of solvated water molecules and picosecond diffusive dynamics around ions. Preliminary results indicate that the terahertz Raman data is at odds with previous pump-probe experiments and various theoretical studies, requiring an overhaul of theoretical models. Our collaboration with Casey Hynes will allow us to influence the development of theoretical work on ionic solvation.
Organisations
Publications
González-Jiménez M
(2016)
Observation of coherent delocalized phonon-like modes in DNA under physiological conditions
in Nature Communications
Sonnleitner T
(2014)
Dynamics of RTILs: A comparative dielectric and OKE study
in Journal of Molecular Liquids
Turton D
(2009)
Universal nonexponential relaxation: Complex dynamics in simple liquids
in The Journal of Chemical Physics
Turton D
(2011)
Rattling the cage: Micro- to mesoscopic structure in liquids as simple as argon and as complicated as water
in Journal of Molecular Liquids
Turton DA
(2012)
Structure and dynamics in protic ionic liquids: a combined optical Kerr-effect and dielectric relaxation spectroscopy study.
in Faraday discussions
Turton DA
(2012)
The dynamic crossover in water does not require bulk water.
in Physical chemistry chemical physics : PCCP
Turton DA
(2009)
Dynamics of imidazolium ionic liquids from a combined dielectric relaxation and optical Kerr effect study: evidence for mesoscopic aggregation.
in Journal of the American Chemical Society
Turton DA
(2008)
Structural relaxation in the hydrogen-bonding liquids N-methylacetamide and water studied by optical Kerr effect spectroscopy.
in The Journal of chemical physics
Turton DA
(2010)
Optical Kerr-effect study of trans- and cis-1,2-dichloroethene: liquid-liquid transition or super-Arrhenius relaxation.
in Physical chemistry chemical physics : PCCP
Turton DA
(2011)
The structure and terahertz dynamics of water confined in nanoscale pools in salt solutions.
in Faraday discussions