scholarly journals Thermal Desorption of Hg Monolayers from Cu(100)

1991 ◽  
Vol 229 ◽  
Author(s):  
Y. J. Kime ◽  
Jiandi Zhang ◽  
P. A. Dowben
Keyword(s):  
Phase Transition ◽  
Thermal Desorption ◽  
Thermal Desorption Spectroscopy ◽  
Two Dimensional ◽  
Inherent Part

AbstractA two dimensional phase transition from one adlayer structure to another is an inherent part of the thermal desorption of one monolayer of Hg on Cu(100). The energetics of this phase transition have been studied using thermal desorption spectroscopy (TDS). The TDS spectra reflect the coexistence of the two structural phases for a range of Hg exposures. The TDS spectra have been analyzed within a Polanyi-Wigner framework modified to account for the phase transition.

scholarly journals Effect of Specimen Geometry on the Thermal Desorption Spectroscopy Evaluated by Two-Dimensional Diffusion-Trapping Coupled Model

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1374
Author(s):  
Yafei Wang ◽  
Songyan Hu ◽  
Guangxu Cheng
Keyword(s):  
Thermal Desorption ◽  
Hydrogen Diffusion ◽  
Coupled Model ◽  
Thermal Desorption Spectroscopy ◽  
Mass Conservation ◽  
Specimen Geometry ◽  
Specimen Preparation ◽  
Two Dimensional ◽  
Dimensional Diffusion ◽  
Transfer Procedures

The hydrogen diffusion process in ferritic steel during thermal desorption tests was simulated using the finite element method based on the two-dimensional diffusion-trapping coupled model. This model was first verified by experimental data to obtain a physically meaningful combination of trap/lattice parameters. Then, the effect of specimen geometry was studied by varying the height of cylindrical specimens with other parameters fixed at constant values. Simulation of desorption spectra with different specimen geometries indicates that the measurement of hydrogen concentration is not affected by the change in specimen geometry due to the mass conservation law, for original thermal desorption spectra (TDS), which are, however, unlikely to be detected in traditional experiments due to the necessity of specimen transfer procedures. Considering the hydrogen escape during rest time (specimen preparation/transfer/evacuation), the measured TDS curves are expected to be strongly dependent on the specimen geometry. The effect of specimen geometry on desorption spectra is more pronounced for smaller specimens, resulting in the dramatic decrease in peak flux and the increased error of Kissinger method in the determination of trap deactivation energy. The present study may contribute to better understanding and more reliable interpretation of the TDS curves by considering the size effect.

Temperature Effect on the Two-Dimensional Phase Transition Kinetics of Adenine Adsorbed at the Hg Electrode/Aqueous Solution Interface

2003 ◽  
Vol 68 (8) ◽  
pp. 1407-1419 ◽  
Author(s):  
Claudio Fontanesi ◽  
Roberto Andreoli ◽  
Luca Benedetti ◽  
Roberto Giovanardi ◽  
Paolo Ferrarini
Keyword(s):  
Phase Transition ◽  
Aqueous Solution ◽  
Phase Change ◽  
Temperature Effect ◽  
Transition Rate ◽  
Effect Of Temperature ◽  
Two Dimensional ◽  
Solution Interface ◽  
Phase Transition Kinetics ◽  
Kinetics Of

The kinetics of the liquid-like → solid-like 2D phase transition of adenine adsorbed at the Hg/aqueous solution interface is studied. Attention is focused on the effect of temperature on the rate of phase change; an increase in temperature is found to cause a decrease of transition rate.

Sign in / Sign up

Export Citation Format

Share Document