학술논문

Following the microscopic pathway to adsorption through chemisorption and physisorption wells.
Document Type
Article
Source
Science; 9/18/2020, Vol. 369 Issue 6510, p1461-1465, 5p, 1 Diagram, 4 Graphs
Subject
Adsorption
Equilibrium
Chemical bonds
Physisorption
Molecular beams
Language
ISSN
00368075
Abstract
Adsorption involves molecules colliding at the surface of a solid and losing their incidence energy by traversing a dynamical pathway to equilibrium. The interactions responsible for energy loss generally include both chemical bond formation (chemisorption) and nonbonding interactions (physisorption). In this work, we present experiments that revealed a quantitative energy landscape and the microscopic pathways underlying a molecule’s equilibration with a surface in a prototypical system: CO adsorption on Au(111). Although the minimum energy state was physisorbed, initial capture of the gas-phase molecule, dosed with an energetic molecular beam, was into a metastable chemisorption state. Subsequent thermal decay of the chemisorbed state led molecules to the physisorption minimum. We found, through detailed balance, that thermal adsorption into both binding states was important at all temperatures. [ABSTRACT FROM AUTHOR]