Phonon-assisted desorption

Fig. 1.37 Schematic explanation of homogenizing mole-fraction ratio x of In tGai tN by phonon-assisted desorption...

G. Lilienkamp and J.P. Toennies. The Observation of One-Phonon Assisted Selective Desorption and Adsorption of He Atoms in Defined Vibrational Levels on a LiF(OOl) Single Crystal Surface. J. Chem. Phys. 78 5210 (1983). 

On the basis of the dressed photon theory and the important role of electric dipole-forbidden molecular vibrational excitations, recent theoretical studies have proposed a simple model to describe atom or atom-cluster desorption due to the dressed photons from a nanometric particle deposited on a substrate [49]. Assuming an anharmonic potential for each atomic binding, an effective atom-nanodot potential was evaluated to determine the desorption energy and the stabilized dot size. The model shows that electric dipole-forbidden molecular vibrational excitations play an important role in the phonon-assisted process, which could potentially lead to a novel fabrication method, in addition to controlling the size and position of nanostructures [51]. 

Alternatively, the scattering excitations may be atomic vibrations. These may result in phonon-assisted sidebands around resonant tunnelling peaks, corresponding to the absorption or emission of phonons. In extreme cases the transfer of electronic energy to atomic motion may produce atom transfer between tip and sample, or even desorption this is a form of DIET (desorption induced by electronic transitions) and may be used to break bonds selectively on surfaces. 

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