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Updated: May 2, 2026
11:33
All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
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Single-molecule infrared spectroscopy with scanning tunneling microscopy.
Kangkai Liang1,2, Zihao Wang1,2, Weike Quan1,2
1Department of Chemistry, University of California, San Diego, La Jolla, CA, USA.
Science (New York, N.Y.)
|February 19, 2026
Summary
This study introduces a new method to observe single-molecule vibrations using infrared light and scanning tunneling microscopy. This technique precisely maps molecular movements and conformational changes, advancing chemical control.
Area of Science:
- Physical Chemistry
- Surface Science
- Spectroscopy
Background:
- Probing single-molecule vibrations is crucial for understanding and controlling chemical reactions in complex environments.
- Existing methods often lack the resolution to observe vibration-mediated nuclear motions at the single-molecule level.
Purpose of the Study:
- To develop and validate a new measurement scheme for characterizing single-molecule vibrations.
- To investigate vibration-mediated nuclear motions and conformational dynamics of molecules.
Main Methods:
- Integration of frequency-tunable infrared excitation with scanning tunneling microscopy (STM).
- Validation using infrared-induced rotation of the ethynyl radical.
- Application to mapping pyrrolidine's conformational dynamics.
Main Results:
- The technique successfully captured fundamental vibrational modes, overtones, and combination bands.
- Isotopic substitutions confirmed the observed spectral features.
- Density functional theory (DFT) calculations revealed that delocalized modes and ring puckering drive pyrrolidine's structural transition.
Conclusions:
- The new experimental platform enables atomic-precision probing of molecular vibrations and transformations.
- Observed selection rules differ from traditional infrared spectroscopy, offering new insights.
- This method opens avenues for precise chemical control at the single-molecule level.
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