Dynamics of individual atomic kinks during crystal dissolution

Area of Science:

• Surface science
• Electrochemistry
• Materials science

Background:

• Solid dissolution and crystallization involve fundamental steps of atom removal and deposition.
• Understanding kink dynamics is crucial for controlling these processes.
• Direct observation of these atomic-scale dynamics has been challenging.

Purpose of the Study:

• To directly observe and quantify the dynamics of kink motion during solid dissolution.
• To investigate the role of atom removal/deposition at individual kinks.
• To measure the kinetic properties of electrochemical reactions at the atomic level.

Main Methods:

• Utilized a novel scanning tunneling microscopy (STM) technique.
• Studied the electrochemical dissolution of Copper(100) in Hydrochloric acid (HCl) solution.
• Monitored local dissolution/redeposition fluctuations at individual kinks.

Main Results:

• Observed pronounced local dissolution/redeposition fluctuations at individual kinks.
• Detected these fluctuations even at the onset of copper dissolution.
• Measured average kink propagation rates of approximately 10^3 atoms/s.
• Measured average kink reaction rates in the range of 10^5 atoms/s.

Conclusions:

• The novel STM technique provides direct access to kink motion dynamics.
• Electrochemical dissolution of Cu(100) exhibits significant atomic-level fluctuations.
• This method allows for direct measurement of fundamental kinetic properties in electrochemical reactions.