Center for Molecular Modeling - L. Meier

Crystallographic control of hydrogen ingress in bcc-iron: Insights from ab initio simulations

lmeier — Tue, 06 Jan 2026 15:07:27 +0000

L. Meier, A.I. Bhatti, L. A. I. Kestens, S. Cottenier

International Journal of Hydrogen Energy

201, 152840

2026

Abstract

Hydrogen uptake into body-centered cubic (bcc) iron as a root cause for subsequent hydrogen embrittlement, is initiated at the surface. In this paper, we quantify how readily H diffuses from the surface into the bulk. We consider a set of 10 different Fe surfaces and treat H-permeation as a two-step process. First, density-functional calculations determine the adsorption energy of an isolated H atom at every crystallographically distinct surface site. Second, for each adsorption site we map the minimum-energy pathway between the surface and the lattice. Across all orientations studied, a clear trend emerges: sites that bind hydrogen most weakly are the starting point of the lowest-barrier diffusion channels into the metal interior. Thus, the least-favorable adsorption pockets act as “gateways” for subsurface penetration. This insight provides a practical design rule: minimizing exposure of such high-energy adsorption motifs should make bcc-iron components less susceptible to hydrogen uptake and the associated embrittlement.

Gold Open Access

DOI

https://doi.org/10.1016/j.ijhydene.2025.152840

Adsorption of Cyclic (Alkyl) (Amino) Carbenes on Monohydride Si(001) Surfaces: Interface Bonding and Electronic Properties

lmeier — Thu, 13 Mar 2025 12:15:50 +0000

L. Meier, W.G. Schmidt

The Journal of Physical Chemistry C

2023

Published while none of the authors were employed at the CMM

Abstract

The adsorption of cyclic (alkyl) (amino) carbenes on the monohydride Si(001) surface is explored within density-functional theory. Two different adsorption mechanisms are investigated: the carbene insertion in Si–H bonds and the binding to a surface defect with missing hydrogen. The relative stability of these configurations depends on the hydrogen chemical potential, i.e., the surface preparation conditions as well as on the molecular side groups. The latter are also found to decisively influence the molecular diffusion. Some adsorption configurations are found to give rise to electronic states within the silicon bulk band gap. A sizable reduction of the work function is found upon molecular adsorption.

Green Open Access

DOI

https://doi.org/10.1021/acs.jpcc.2c07316

Band Alignment at Ga x In 1–x P/Al y In 1–y P Alloy Interfaces from Hybrid Density Functional Theory Calculations

lmeier — Thu, 13 Mar 2025 12:10:56 +0000

L. Meier, C. Braun, T. Hannappel, W.G. Schmidt

physica status solidi (b)

2020

Published while none of the authors were employed at the CMM

Abstract

The composition dependence of the natural band alignment at the Ga_xIn_1–xP/Al_yIn_1–yP alloy interface is investigated via hybrid functional based density functional theory. The direct–indirect crossover for the Ga_xIn_1–xP and Al_yIn_1–yP alloys is calculated to occur for x = 0.9 and y = 0.43. The calculated Ga_xIn_1–xP/Al_yIn_1–yP interface band alignment shows a crossover from type-I to type-II with increasing Ga content x. The valence band offset is essentially positive irrespective of the alloy compositions, and amounts up to 0.56 eV. The conduction band offset varies between −0.85 and 1.16 eV.

Gold Open Access

DOI

https://doi.org/10.1002/pssb.202000463

GaInP/AlInP(001) Interfaces from Density‐Functional Theory

lmeier — Thu, 13 Mar 2025 12:08:20 +0000

L. Meier, W.G. Schmidt

Physica Status Solidi (b) - Basic Solid State Physics

2021

Published while none of the authors were employed at the CMM

Abstract

The band alignment and the electronic states at the GaInP/AInP(001) interface are explored with (hybrid) density functional theory. Thereby, CuPt-type ordered crystals are focused. For the most stable interface, valence and conduction band offsets of 0.04 and −0.58 eV, respectively, are predicted. No interface states occur within the fundamental gap. Generally, the results support the validity of natural band offsets and demonstrate a minor influence of strain and local bonding scenarios on the band alignment.

Gold Open Access

DOI

https://doi.org/10.1002/pssb.202100462

Adsorption of Cyclic (Alkyl) (Amino) Carbenes on Monohydride Si(001) Surfaces: Interface Bonding and Electronic Properties

lmeier — Thu, 13 Mar 2025 12:04:03 +0000

L. Meier, W.G. Schmidt

The Journal of Physical Chemistry C

127, 4, 1973-1980

2023

Published while none of the authors were employed at the CMM

Abstract

Green Open Access

DOI

http://dx.doi.org/

Surface-to-bulk hydrogen transport in BCC iron: a computational review of adsorption and diffusion mechanisms

lmeier — Thu, 13 Mar 2025 11:00:35 +0000

L. Meier, A.I. Bhatti, S. Cottenier

Critical Reviews in Solid State and Materials Sciences

2024

Abstract

Hydrogen embrittlement poses a significant challenge in various engineering applications. In this context, the iron/hydrogen system serves as a crucial prototype for examining the interaction between hydrogen and steel. Despite the critical importance of this topic, there is a notable lack of knowledge regarding the influence of surface characteristics on the penetration of hydrogen into materials. To address this gap, we have conducted an extensive review of the existing literature, particularly focusing on how different surface orientations of body-centered cubic (bcc) iron affect the adsorption, diffusion, and subsequent penetration of hydrogen into an iron crystal. The review primarily focuses on computational methods, incorporating experimental data for comparative analysis wherever feasible. This comprehensive synthesis of scattered information leads to several key conclusions. First, there is a systematic relationship between surface geometry and adsorption energy that has previously been overlooked. Second, bulk diffusion characteristics are recovered just a few atomic layers beneath the surface, emphasizing the importance of the initial surface layers in determining initial penetration. Third, penetrating through the surface layers is generally more challenging than further diffusion through bulk iron, with the specifics heavily dependent on the surface orientation. Studies on high-index surfaces are limited. We identify this as an area needing further research, and this review provides a solid foundation for such studies.

This work has been performed as part of the NOHENTRY project, funded by the Energy Transition Fund (Energietransitiefonds) of the Directorate-General Energy (Algemene Directie Energie) of the Federal Public Service for the Economy (FOD Economie) of Belgium. S.C. acknowledges financial support from OCAS NV by an OCAS-endowed chair at Ghent University. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Research Foundation - Flanders (FWO) and the Flemish Government - department EWI.

Gold Open Access

DOI

https://doi.org/10.1080/10408436.2024.2416435

Hydrogen Diffusion through iron surfaces

lmeier — Mon, 26 Jan 2026 13:20:21 +0000

L. Meier, A.I. Bhatti, S. Cottenier

ISBN/ISSN:

Poster

Conference / event / venue

FEARS: Faculty of Engineering and Architecture Research Symposium

Ghent, Belgium

Thursday, 26 October, 2023

A combined computational and experimental approach to understanding the surface effect in permeation experiments

lmeier — Tue, 14 Oct 2025 09:55:43 +0000

L. Meier, R. Dedoncker, K. Van den Bergh, S. Cottenier, L. Duprez (OCAS NV)

ISBN/ISSN:

Talk

Conference / event / venue

5th International Conference on Metals and Hydrogen (SteelyHydrogen)

Ghent, Belgium

Tuesday, 14 October, 2025 to Thursday, 16 October, 2025

Crystallographic Control of Hydrogen Ingress in BCC-Iron: Insights from Ab-Initio Simulations

lmeier — Tue, 03 Jun 2025 15:07:00 +0000

L. Meier, A.I. Bhatti, S. Cottenier

ISBN/ISSN:

Talk

Conference / event / venue

1st Conference on Hydrogen in Materials Science and Engineering (H2MSE)

Siegburg (DE)

Tuesday, 11 February, 2025 to Thursday, 13 February, 2025

Crystallographic Control of Hydrogen Ingress in BCC-Iron: Insights from Ab-Initio Simulations

lmeier — Tue, 03 Jun 2025 15:05:02 +0000

L. Meier, A.I. Bhatti, L. Kestens, S. Cottenier

ISBN/ISSN:

Poster

Conference / event / venue

ASTM Conference on Hydrogen in Materials

La Rochelle (Fr)

Tuesday, 3 June, 2025 to Friday, 6 June, 2025