Photo- and Thermodesorption of Helium on Pt(111)

Abstract

In a detailed study of thermal desorption of monolayers of both 4He and 3He adsorbed on Pt(111) (binding energy about 9 meV), we have observed photodesorption induced by the blackbody radiation from a room temperature environment. This process proceeds independently of the thermal desorption. Theoretical treatments of both thermal and photodesorption are given and agree very well with the data in all important aspects. We conclude that the photodesorption is due to direct coupling of photons to the adsorbate.

Quantum Dynamical Approach to Ultrafast Molecular Desorption from Surfaces

“…In the first case, either infrared (IR) or, more commonly, ultraviolet/visible (UV/vis) photons 1 couple directly to the dipole or transition dipole moment of the adsorbate−substrate complex. For weakly bound adsorbates, the black body radiation at ambient temperatures suffices to induce direct desorption. , Direct excitation is also the rule for IR excitation, even at metal surfaces, which frequently act as “mirrors” for IR photons. On the other hand, in UV/vis, direct excitation only dominates for semiconductor or insulating surfaces.…”

Vibrationally enhanced associative photodesorption of molecular hydrogen from Ru(0001)

“…In this system the adsorbate-substrate coupling is due to phonons and weak, leading to comparatively long (vibrational) lifetimes, s vib , in the ns range. (Direct desorption by blackbody radiation, of very weakly bound, physisorbed H 2 [23] and He has also been achieved [24].) It is the purpose of this paper: (i) to find out whether IR control in a strongly coupled, chemisorbed system with much shorter vibrational lifetimes is possible (s vib 6 1 ps), and (ii) if so, can affect the subsequent photoreaction via an electronic excited state with an electronic lifetime s el as short as a few fs.…”

Surface stress of graphene layers supported on soft substrate

“…Surface stress of solids, which connects the macroscopic properties of solids and the chemical bonding state at a surface or an interface 1 2 3 , plays an important role in many surface phenomena such as elastic moduli of nanoscale materials 4 5 6 , surface reconstruction of metals 7 8 , shape transitions of nanoparticles 9 , surface diffusion, epitaxial growth 10 , self-assembled domain patterns 11 , deformation of nanoporous materials 12 13 , bending of layered cantilevers 14 15 , contacts of soft matters 16 , and stiffening of solids by surface stress 17 18 . Another important surface property is surface energy, and the relation between surface stress and surface energy is elaborated in many papers 2 3 4 .…”