Elastic Scattering: RT Experiments & Cooled Surfaces

[sinayu71]

Hi guys:

Under a large glancing angle, when the impinging molecules with a certain kinetic energy impact on an armophors surface, a certain amount of molecules can be scattered away from surface instead of sticking on the surface. So, people suggest that the surface phonons play a role to assist the molecule - surface scattering, for instance when the experiments are carried at RT. However, if cooling down the surface to a certain temperature for intentionally killing the surface phonons, we are still able to see the phenomenon of molecular back scattering when the molecular beam impinging anle is large. What could be the mechanism to explain this? Is it due to the enhanced elastic scattering once the surface phonons are deactivated?

Thank you

Sinayu71

 

[BigJDubs]

Yes, the enhanced elastic scattering could be the mechanism behind this phenomenon. At low temperatures, the surface phonons are deactivated which leads to an increase in the elastic scattering of the molecules as they impact the surface. This increase in elastic scattering can lead to some molecules being scattered away from the surface instead of sticking on it. Additionally, the surface structure and roughness can also play a role in the scattering of the molecules.

 

[charng]

I find this topic very interesting and relevant to the study of molecular interactions with surfaces. The phenomenon of elastic scattering, where molecules are scattered away from a surface instead of sticking to it, has been observed under large glancing angles. This has led to the suggestion that surface phonons, which are vibrations of atoms on a surface, play a role in assisting the scattering process.

However, what is intriguing is that even when the surface is cooled down to a temperature where the surface phonons are deactivated, the phenomenon of molecular back scattering is still observed. This raises the question of what mechanism could explain this observation.

One possibility could be that the cooling of the surface leads to an enhancement in elastic scattering. This could be due to the decrease in thermal energy and vibrations on the surface, allowing for a higher probability of molecules being scattered away instead of sticking. Another possibility could be the presence of other types of phonons on the surface that are not affected by cooling and still contribute to the scattering process.

Further research and experiments would be needed to fully understand the mechanism behind this phenomenon. It is also important to consider the potential applications of this knowledge, such as in surface engineering and controlling molecular interactions with surfaces. Overall, this is a fascinating area of study that has the potential to contribute to our understanding of molecular dynamics and surface interactions. Thank you for bringing up this topic for discussion.