Prominent out-of-plane diffraction in helium scattering from a methyl-terminated Si(111) surface. Issue 28 (9th July 2019)

• Record Type: Journal Article
• Authors: del Cueto, Marcos; Muzas, Alberto S.; Frankcombe, Terry J.; Martín, Fernando; Díaz, Cristina
• Is Part Of: Physical chemistry chemical physics. Volume 21:Issue 28(2019)
• Page Start: 15879
• Page End: 15887
• Publication Date: 2019-07-09
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c9cp02141h
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Out-of-plane diffraction widely surpasses in-plane diffraction in helium atom scattering from methyl-terminated Si(111) surfaces. Abstract : Due to their electrochemical and oxidative stability, organic-terminated semiconductor surfaces are well suited to applications in, for example, photoelectrodes and electrochemical cells, which explains the lively interest in their detailed characterization. Helium atom scattering (HAS) is a useful tool to carry out such characterization. Here, we have simulated HAS in He/CH3 –Si(111) based on density functional theory (DFT) potential energy surfaces (PESs) and multi-configuration time-dependent Hartree (MCTDH) dynamics. Our analysis of HAS shows that most diffraction taking place in this system corresponds to high-order out-of-plane peaks. This is a general trend that does not depend on the specific features of the simulations, such as the inclusion or not of the van der Waals long-range effects. This is the first and only He-surface system for which such huge out-of-plane diffraction has been described. This striking theoretical finding should encourage new experimental developments to confirm this previously unreported effect.