jz1c01595_si_001.pdf (3.47 MB)
Lifetime-Associated Two-Dimensional Infrared Spectroscopy Reveals the Hydrogen-Bond Structure of Supercooled Water in Soft Confinement
journal contribution
posted on 2021-06-22, 21:15 authored by Federico Caporaletti, Daniel Bonn, Sander WoutersenWe demonstrate a
method to address the problem of spectral overlap
in multidimensional vibrational spectroscopy and use it to investigate
supercooled aqueous sorbitol solutions. The absence of crystallization
in these solutions has been attributed to “soft” confinement
of water in subnanometer voids in the sorbitol matrix, but the details
of the hydrogen-bond structure are still largely unknown. 2D-IR spectroscopy
of the OH-stretch mode is an excellent tool to investigate hydrogen
bonding, but in this case it seems difficult because of the overlapping
water and sorbitol contributions to the 2D-IR spectrum. Using the
difference in OH-stretch lifetimes of water and sorbitol we can cleanly
separate these contributions. Surprisingly, the separated 2D-IR spectra
show that the hydrogen-bond disorder of soft-confined water is independent
of temperature and decoupled from its orientational order. We believe
the approach we use to separate overlapping 2D-IR spectra will enhance
the applicability of 2D-IR spectroscopy to study multicomponent systems.
History
Usage metrics
Categories
Keywords
Supercooled WaterHydrogen-Bond Structure2 D-IR spectrum2 D-IR spectroscopyhydrogen-bond disordersorbitol solutionsSoft Confinementstudy multicomponent systemshydrogen-bond structuresorbitol contributions2 D-IR spectra2 D-IR spectra showOH-stretch modevibrational spectroscopyOH-stretch lifetimessoft-confined waterLifetime-Associated Two-Dimensionalsorbitol matrixorientational order