Researchers Develop Technique to Hear Single Molecules

New infrared-integrated scanning tunneling microscopy allows scientists to detect vibrations of individual molecules.

Published on Feb. 27, 2026

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Researchers at the University of California San Diego, led by Assistant Professor of Chemistry Shaowei Li, have developed a new technique called infrared-integrated scanning tunneling microscopy (IRiSTM) that allows them to detect the vibrations of individual molecules. This breakthrough in single-molecule infrared spectroscopy brings scientists one step closer to controlling chemical reactions at the most fundamental level by targeting specific molecular bonds.

Why it matters

Traditional infrared spectroscopy can only detect the collective vibrations of millions or billions of molecules at once. The ability to observe the unique vibrational "fingerprint" of a single molecule opens up new possibilities for steering chemical reactions along desired pathways and controlling molecular motion at the nanoscale.

The details

The IRiSTM technique combines infrared excitation with scanning tunneling microscopy, a method best known for imaging individual atoms and molecules by measuring the quantum tunneling of electrons between a sharp metal tip and a surface. This allows researchers to detect the faint vibrations of a single molecule, which reflects not only its chemical structure but also the nanoscale environment around it.

  • The research was led by Shaowei Li, an Assistant Professor of Chemistry at the University of California San Diego.

The players

Shaowei Li

An Assistant Professor of Chemistry at the University of California San Diego who led the research team that developed the infrared-integrated scanning tunneling microscopy (IRiSTM) technique.

University of California San Diego

The university where the research team that developed the IRiSTM technique is based.

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What they’re saying

“Infrared spectroscopy is one of our most powerful tools, but until now it has always been an ensemble technique. This gives us a way to see, at the most fundamental level, how vibrational energy couples to molecular motion.”

— Shaowei Li, Assistant Professor of Chemistry (Mirage News)

The takeaway

The development of the IRiSTM technique represents a significant advancement in single-molecule spectroscopy, allowing scientists to observe the unique vibrational signatures of individual molecules. This breakthrough could lead to new insights into chemical reactions and the ability to control molecular motion at the nanoscale.