Related Experiment Video
Updated: Jan 7, 2026

Analysis of Complex Molecules and Their Reactions on Surfaces by Means of Cluster-Induced Desorption/Ionization Mass Spectrometry
Published on: March 1, 2020
Molecular Decoupling and Surface Coverage Synergistically Contribute to the Volcano-Shaped Probability of
Xiaoxuan Zheng1,2, Junjun Tan2, Jing Lai1
1Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
Abstract:
Deciphering single-molecule-level chemical reactions at surfaces requires elucidating the synergistic effect of molecular decoupling and spatial distribution. However, this can only be achieved using a limited number of experimental techniques. Here, we demonstrate for the first time that nanocavity-enhanced sum-frequency generation vibrational imaging provides a powerful tool for visualizing both molecular decoupling and spatial distribution of ultralow-concentration molecules in plasmonic nanocavities. Using 4-nitrothiophenol as a model system, we observed a pronounced aggregation effect in molecular self-assembly and a volcano-shaped reaction probability curve in interfacial single-molecule-level chemical reactions. This volcano shape arises from the balance between two competing factors: enhanced reactivity due to molecular decoupling and decreased reaction probability due to reduced molecular availability. This study establishes a molecular-level correlation between intermolecular coupling, surface coverage, and reactivity, thereby paving the way for investigating and manipulating interfacial single-molecule-level chemical reactions.
Related Concept Videos
Factors Affecting Dissolution: Particle Size and Effective Surface Area
Theories of Dissolution: The Danckwerts' Model and Interfacial Barrier Model
Radical Reactivity: Overview
Temperature Dependence on Reaction Rate
Atoms, molecules, or ions must collide before they can react with each other. Atoms must be close together to form chemical bonds. This premise is the basis for a theory that explains many observations regarding chemical kinetics, including factors affecting reaction rates.
The collision theory is based on the postulates that (i) the reaction rate is proportional to the rate of reactant collisions, (ii) the reacting species collide in an orientation allowing contact between...
Predicting Reaction Outcomes
Phase Transitions: Vaporization and Condensation

