PETRA III Science Seminar | Can reflectometry from liquid surface be replaced by grazing incidence diffuse scattering?

by Chen Shen (DESY Photon Science)

Tuesday 20 Jun 2023, 14:15 → 15:00 Europe/Berlin

Online

 

Liquid surfaces serve as model systems and also reaction platforms in many applications, ranging from basic surface science [1] to biophysics [2], electrochemistry [3] and synthesis of novel electronics [4]. Traditionally the layering structure is often obtained by reflectometry. As the reflectivity drops as the 4^th power on Q_z, the method suffers from low signal-noise ratio at the high Q_z range that is needed for structural analysis. Moreover, the decreasing footprint with the increase of Q_z changes the resolution and also causes radiation induced chemistry. At the High-resolution Diffraction beamline P08, we use our Langmuir grazing incidence diffraction setup [5] to demonstrate that for Langmuir films on simple liquid surfaces, diffuse scattering at a fixed grazing incidence geometry can provide the same layer structure as obtained from reflectometry [6,7]. We develop a simple formula to calculate the diffuse scattering data back into a reflectivity curve at any given resolution to allow users to use their old reflectivity analysis software. Furthermore, we advance a more comprehensive formula to calculate the surface height-height correlation spectrum in addition to the phenomenological Gaussian roughness. The formula is universal and can be applied to other surface diffraction instruments elsewhere. 

 

references:

[1]          M. K. Sanyal, S. K. Sinha, K. G. Huang, and B. M. Ocko, Phys Rev Lett 66, 628 (1991).

[2]          C. Stefaniu, G. Brezesinski, and H. Mohwald, Advances in colloid and interface science 208, 197 (2014).

[3]          A. Sartori, R. P. Giri, H. Fujii, S. C. Hövelmann, J. E. Warias, P. Jordt, C. Shen, B. M. Murphy, and O. M. Magnussen, Nat. Commun. 13 (2022).

[4]          L. Wang, H. Sahabudeen, T. Zhang, and R. Dong, npj 2D Materials and Applications 2 (2018).

[5]          C. Shen, R. Kirchhof, and F. Bertram, Journal of Physics: Conference Series 2380, 012047 (2022).

[6]          S. Mora, J. Daillant, D. Luzet, and B. Struth, Europhys. Lett. 66, 694 (2004).

[7]          P. S. Pershan, Colloids and Surfaces A: Physicochemical and Engineering Aspects 171, 149 (2000).