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Updated: Jul 19, 2026
10:28
Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy
Published on: May 27, 2018
Long-lived interfacial vibrations of water
The Journal of Physical Chemistry. B
|October 13, 2006
Summary
Long-lived OH-stretch excitations in water were observed after laser ablation. These excitations, found on interfacial water molecules with broken hydrogen bonds, persist for over 200 ps.
Area of Science:
- Physical Chemistry
- Spectroscopy
- Ultrafast Laser Dynamics
Background:
- Investigating vibrational dynamics of water molecules is crucial for understanding chemical reactions and biological processes.
- Ultrafast laser ablation provides a unique method to probe water's excited states.
- Mid-infrared pulses tuned to the OH-stretch absorption maximum can selectively excite specific vibrational modes.
Discussion:
- The observed OH-stretch excitations exhibit a narrowed and blue-shifted spectrum compared to equilibrium water.
- The excited-state lifetime of these OH-stretch excitations is significantly longer (>200 ps) than in bulk water (0.2 ps).
- Rapid decrease in water density during ablation breaks hydrogen bonds, leading to long-lived interfacial species.
Key Insights:
- Long-lived OH-stretch (nu(OH)) excitations (v = 1) were detected in water following mid-infrared laser ablation.
- Incoherent anti-Stokes Raman spectroscopy revealed a narrowed (100 cm(-1) fwhm) and blue-shifted (3600 cm(-1) peak) transition for these excitations.
- The prolonged excited-state lifetime is attributed to OH-stretch excitations on interfacial water molecules with disrupted hydrogen bonding.
Outlook:
- Further investigation into the structural and dynamic properties of interfacial water under ablation conditions.
- Exploring potential applications of long-lived vibrational excitations in areas like energy transfer and catalysis.
- Developing advanced spectroscopic techniques to probe water dynamics at interfaces with higher resolution.
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