Adsorbate-Induced Restructuring of the Fe(100) Surface: Model Cluster Studies

Arabczyk, W.; Rausche, E.; Storbeck, F.

doi:10.12693/aphyspola.81.109

Cited by 7 publications

(5 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Arabczyk and Rausche studied carbon atom adsorption on Fe(110) using extended Hückel theory (EHT) within a cluster model. 11 We will compare our results with theirs, demonstrating that EHT, essentially the tight-binding method, is not accurate enough to yield the correct site preference for carbon on Fe(110). Sorescu et al 12 studied the interaction of carbon with Fe(100) when they were investigating CO adsorption on Fe(100) with gradient-corrected density-functional theory (DFT) and ultrasoft pseudopotentials.…”

Section: Introductionmentioning

confidence: 96%

Carbon atom adsorption on and diffusion into Fe(110) and Fe(100) from first principles

2005

View full text Add to dashboard Cite

We employ spin-polarized periodic density functional theory (DFT) to examine carbon atom adsorption on, absorption in, and diffusion into Fe(110) and Fe(100). We find that carbon atoms bind strongly with Fe surfaces and prefer high coordination sites. The carbon atom is predicted to adsorb on the long-bridge site on Fe(110) and the fourfold hollow site on Fe(100). Due to the very short distance between the carbon atom and the subsurface Fe atom of Fe(100), the carbon atom binds more strongly with Fe(100) than with Fe(110). In the subsurface region, the carbon atom prefers the octahedral site, as in bulk Fe. We find that the carbon atom is more stable in the subsurface octahedral site of Fe(110) than that of Fe(100), since the strain caused by the interstitial carbon atom is released by pushing one surface Fe atom towards vacuum by 0.5 Å in Fe(110), while the distortion in Fe(100) propagates far into the lattice. Diffusion of carbon atoms into Fe(110) and Fe(100) subsurfaces goes through transition states where the carbon atom is coordinated to four Fe atoms. The barriers to diffusion into Fe(110) and Fe(100) are 1.18 eV and 1.47 eV, respectively. The larger diffusion barrier into Fe(100) is mainly due to the stronger bonding between carbon and the Fe(100) surface. We predict that the rate-limiting step for C incorporation into bulk Fe is the initial diffusion to subsurface sites, while the ratelimiting step for absorbed carbon segregation to the surface is bulk diffusion, with no expected difference between rates to segregate to different surfaces. Lastly, we predict that graphite formation will be more favorable on C-covered Fe(110) than C-covered Fe(100).

show abstract

Section: Introductionmentioning

confidence: 96%

Carbon atom adsorption on and diffusion into Fe(110) and Fe(100) from first principles

2005

View full text Add to dashboard Cite

show abstract

“…During the last decade remarkable progress has been achieved in the field of computer simulation and important problems in surface physics, catalysis and metallurgy were addressed. Several theoretical methods have been applied to study hydrogen interactions, such as effective medium theory [10], molecular dynamics [11], modified intermediate neglect of differential overlap (MINDO/SR) [12], intermediate neglect of differential overlap (INDO) [13] and extended Hückel methods [14][15][16]. The problems of vacancy-hydrogen interaction and hydrogen paring in transition metals have been studied before using both first principles calculations based on cluster models and effective medium theory [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

A computational study of H-Fe vacancy interaction

Pistonesi

García

Brizuela

et al. 1998

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

The semi-empirical atom superposition and electron delocalization molecular orbital (ASED-MO) theory was used to study the H-Fe interaction near a Fe vacancy. Calculations were carried out using clusters of the type and simulating the absorption of a hydrogen atom near a vacancy located at the centre of the cluster. The formation of H-H pairs was also considered. Our calculations involve a system in which experiments are difficult to perform and could contribute to a better understanding or insight based on microscopic exploration. The results indicate that in general the H-Fe interaction gets stronger when the H atom is close to the vacancy but not at its centre due to a strong indirect interaction mediated by the Fe matrix. Minima regions are obtained at eccentric positions. A H-H pair is suggested to be formed near the vacancy region. The relaxation of the first neighbour Fe atoms towards the vacancy is also addressed in the presence and absence of H. For all situations studied, the most stable configuration corresponds to a cluster contraction.

show abstract

“…Interactions of hydrogen with lattice imperfections in crystalline metals and semiconductors has been reviewed by Myers et al [10]. Several theoretical methods have been applied to study interactions of hydrogen in transitions metals such as effective medium theory [11], modified intermediate neglect of differential overlap (MINDO/SR) [12], intermediate neglect of differential overlap (INDO) [13], extended Hückel (EH) methods [14][15][16] and phenomenological oscillator potentials [17]. The problems of vacancy-hydrogen interaction and hydrogen paring in transition metals have been studied using both first-principles calculations based on cluster models and effective medium theory [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

A theory of hydrogen trapping in a faulted zone of FCC iron

Moro

Obiol

Roviglione

et al. 1998

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

The energetics of hydrogen atoms interacting with a cluster model of -Fe, having a stacking fault zone, have been investigated. The system energy is calculated using the atom superposition and electron delocalization molecular orbital (ASED-MO) method. By modifying the geometrical positions of the impurity within the cluster we found that H occupies nearly octahedral sites on a stacking fault plane. A second H residing near the former and the possible formation of H-H pairing is also addressed. The relative stability of H-H pairs in the iron matrix is compared with that of the molecule, in the vacuum.

show abstract

Adsorbate-Induced Restructuring of the Fe(100) Surface: Model Cluster Studies

Cited by 7 publications

References 27 publications

Carbon atom adsorption on and diffusion into Fe(110) and Fe(100) from first principles

Carbon atom adsorption on and diffusion into Fe(110) and Fe(100) from first principles

A computational study of H-Fe vacancy interaction

A theory of hydrogen trapping in a faulted zone of FCC iron

Contact Info

Product

Resources

About