Single-molecule infrared spectroscopy with scanning tunneling microscopy

Probing vibrations at the single-molecule level is essential for achieving bond-specific chemical control. Here, we introduce a new measurement scheme that integrates frequency-tunable infrared excitation with scanning tunneling microscopy to characterize vibration-mediated nuclear motions of single molecules. We first validated the technique by monitoring the infrared-induced rotation of the ethynyl radical, and then applied it to pyrrolidine, mapping its conformational dynamics. The resulting broadband spectra captured fundamental vibrational modes together with rich overtone and combination bands inaccessible by conventional methods, confirmed with isotopic substitutions. Density functional theory calculations showed that delocalized modes coupled with pyrrolidine ring puckering drive the structural transition, revealing altered selection rules compared to traditional infrared spectroscopy. This new experimental platform enables probing of molecular vibrations and transformations wit..., , # Single-molecule infrared spectroscopy with scanning tunneling microscopy

Dataset DOI: [10.5061/dryad.cfxpnvxmn](https://doi.org/10.5061/dryad.cfxpnvxmn)

## Data overview

This dataset contains raw and processed data supporting the manuscript **“Single-molecule infrared spectroscopy with scanning tunneling microscopy”**. The study introduces **Infrared Integrated Scanning Tunneling Microscopy (IRiSTM)** to characterize vibration-mediated nuclear motions of **single molecules**—specifically **ethynyl radicals** and **pyrrolidine**—on a Cu(100) surface.

Included materials:

* **Raw STM scans**: Nanonis `.sxm`
* **Processed vibrational action/switching spectra & occupation metrics**: `.xlsx`
* **Origin project for photocurrent mapping**: `.opju`
* **Two archives**: home-built software + point-by-point raw IRiSTM datasets (`.zip`)

Files are organized primarily by **manuscript figure number** and can be interpreted independently using the definitions below.

## Contents

* [File organiz...,