DIET at the nanoscale
Graphical abstract
Introduction
Initiating the so-called DIET (desorption induced by electronic transitions) studies is certainly one of the major achievements of Dietrich Menzel. The investigation of the desorption of adsorbed molecules from surfaces induced by electronic excitation began in the early 1960s [1], [2]. At that time, these studies were motivated mainly by the need to improve the ion gauge technology for measuring ultra-high vacuum pressures. The stimulated desorption model proposed by Menzel, Gomer and Redhead [1], [2] was the starting point of all DIET studies [3], [4], and their impact has grown continuously over the past 50 years. Why have the MGR (Menzel, Gomer, Redhead) model and the ensuing DIET studies been so successful over the years? The fundamental reason is that the MGR model and DIET are the foundation of all surface science studies involving the excited states of adsorbates. They offer a generic understanding [5] of all kinds of atomic or molecular dynamic processes at surfaces (desorption, diffusion, dissociation, isomerization, chemical reactions, etc.) stimulated by synchrotron radiation [6], electron impact [7], ion impact [8], and lasers [9].
Section snippets
DIET at the nanoscale
In April 1990, while one of us (G.D.) was spending a month visiting Menzel's laboratory at the T.U.M. (Technical University of Munich), D.M. Eigler at IBM published his famous article “Writing with atoms” [10]. This was the brilliant demonstration that the tip of an STM (Scanning Tunneling Microscope) could be used to move individual atoms and molecules in a controlled manner laterally across a surface. However, it should be remembered that a few years before, in 1987, it had been demonstrated
Inelastic electron tunneling
Inelastic electron tunneling (IET) is the key excitation mechanism of DIET at the nanoscale. Most of the electrons that tunnel between the STM tip and the surface do so elastically without losing any energy. However, there is a fraction of the electrons which tunnel inelastically by releasing a part of their energy into the surface or the adsorbate on the surface. This released energy can be used to activate DIET at the nanoscale.
Two distinct inelastic IET processes can be distinguished,
Future trends of DIET at the nanoscale
DIET at the nanoscale is concerned with the various processes of “Dynamics at surfaces Induced by Electronic Transitions”. Together, resonant and radiant IET with the STM enable a very broad range of phenomena at the atomic-scale to be investigated. These include molecular dynamics (dissociation, desorption, isomerization [48], displacement, chemical reactions), vibrational spectroscopy and dynamics, spin spectroscopy and manipulation, luminescence spectroscopy and very recently Raman
Acknowledgments
We thank our former and present Ph.D. students and postdoctoral researchers who have contributed to the success of this research work, Shuiyan Cao, Heejun Yang, Mathieu Lastapis, Amandine Bellec, Guillaume Baffou, Marta Martin, Franck Rose, Laetitia Soukiassian, Marion Cranney, Franco Chiaravalloti, Tao Wang, Yang Zhang, and Benoît Rogez. This work is also the result of fruitful collaborations with Genevieve Comtet, Marie-Laure Bocquet, Lucette Hellner, Philippe Sonnet, Phaedon Avouris, Robert
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