Related Experiment Video
Updated: Jun 1, 2026

Neutron Crystallography Data Collection and Processing for Modelling Hydrogen Atoms in Protein Structures
Published on: December 1, 2020
Calculation of inelastic helium atom scattering from H2/NaCl(001)
L W Bruch1, F Y Hansen, F Traeger
1Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706, USA.
Helium atom scattering theory was adapted for p(1x1) square lattices, re-analyzing para-hydrogen on NaCl(001). A modified potential series improved calculations for corrugated surfaces, revealing new phonon mode intensity insights.
Area of Science:
- Surface science
- Condensed matter physics
- Scattering theory
Background:
- Low energy helium atom scattering (LEHAS) is a surface-sensitive probe.
- Previous studies focused on triangular lattices, with limited data on square lattices.
- The H(2)/NaCl(001) system presents a computationally challenging corrugated surface.
Purpose of the Study:
- Adapt LEHAS theory for p(1x1) commensurate square lattices.
- Re-analyze experimental data for para-H(2)/NaCl(001).
- Investigate phonon mode excitation and intensity variations on corrugated surfaces.
Main Methods:
- Theoretical adaptation of one-phonon inelastic LEHAS.
- Wave-packet scattering calculations with coupled channels.
- Development of a modified truncated Fourier expansion for the helium-target potential.
- Analysis of experimental data for para-H(2)/NaCl(001).
Main Results:
- Relative intensities of energy loss peaks (6-9 meV) for para-H(2)/NaCl(001) were determined.
- A modified potential series enabled convergence for the corrugated H(2)/NaCl(001) surface.
- Shear horizontal phonon mode was accessed with slight misalignment.
- Longitudinal acoustic phonon mode intensity exceeded shear horizontal mode intensity at 1° misalignment.
Conclusions:
- The adapted LEHAS theory is effective for p(1x1) square lattices.
- Computational challenges of corrugated surfaces can be overcome with modified potential representations.
- Phonon mode excitation and relative intensities are sensitive to surface corrugation and scattering conditions.
More Related Videos
14:11Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis
Published on: March 29, 2016
11:27Studying Soft-matter and Biological Systems over a Wide Length-scale from Nanometer and Micrometer Sizes at the Small-angle Neutron Diffractometer KWS-2
Published on: December 8, 2016
Related Concept Videos
Nuclear Binding Energy
Hess's Law
Atomic Nuclei: Nuclear Spin State Population Distribution
Molecular Orbital Theory II
Van der Waals Equation
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
High-Resolution Mass Spectrometry (HRMS)