Limits...
Modeling the intrusion of molecules into graphite: Origin and shape of the barriers.

Huber SE, Probst M - Int J Mass Spectrom (2014)

Bottom Line: We compare the energy barriers encountered by these molecular projectiles with the ones that are obtained for atomic H, Be, C and O.Furthermore, for some of the species fragmentation is observed.Implications with respect to plasma-surface interaction are discussed.

View Article: PubMed Central - PubMed

Affiliation: Institute of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.

ABSTRACT

We performed density functional theory calculations to explore the energetic and geometric aspects of the permeation of H2, BeH x , OH x (x = 1, 2) and CH y (y = 1-4) through the central hexagon of coronene. Coronene serves as a cluster model for extended graphene which can be regarded as the first layer of a graphite (0 0 0 1) surface. We compare the energy barriers encountered by these molecular projectiles with the ones that are obtained for atomic H, Be, C and O. The barriers are substantially lower if projectiles possess free valences that can bind to the carbon entity. Furthermore, for some of the species fragmentation is observed. Implications with respect to plasma-surface interaction are discussed.

No MeSH data available.


Related in: MedlinePlus

Energy barriers obtained for the permeation of (a) Be, (b) BeH and (c) BeH2 through coronene. The total barriers are decomposed into the deformation energy Edef accounting for geometrical changes in the coronene molecule and the rest energy ΔE according to Eq. (2). The latter contribution is denoted simply as “difference” in the figure. (For interpretation of the references to color in the text, the reader is referred to the web version of the article.)
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4375830&req=5

fig0015: Energy barriers obtained for the permeation of (a) Be, (b) BeH and (c) BeH2 through coronene. The total barriers are decomposed into the deformation energy Edef accounting for geometrical changes in the coronene molecule and the rest energy ΔE according to Eq. (2). The latter contribution is denoted simply as “difference” in the figure. (For interpretation of the references to color in the text, the reader is referred to the web version of the article.)

Mentions: In Fig. 3, we depict the energy barriers for permeation of (a) Be, (b) BeH and (c) BeH2 through the center of coronene (black lines augmented with circles). For simplicity, we plot only the barriers obtained at the PBE0/3-21G level of theory (solid lines) as the curves obtained at the B3LYP/6-31G level of theory yield generally very similar results. In Fig. 3(b), however, we show also the data obtained with B3LYP/6-31G as for the PBE0/3-21G calculations beyond z = 1.2 Å no SCF-convergence could be achieved.


Modeling the intrusion of molecules into graphite: Origin and shape of the barriers.

Huber SE, Probst M - Int J Mass Spectrom (2014)

Energy barriers obtained for the permeation of (a) Be, (b) BeH and (c) BeH2 through coronene. The total barriers are decomposed into the deformation energy Edef accounting for geometrical changes in the coronene molecule and the rest energy ΔE according to Eq. (2). The latter contribution is denoted simply as “difference” in the figure. (For interpretation of the references to color in the text, the reader is referred to the web version of the article.)
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4375830&req=5

fig0015: Energy barriers obtained for the permeation of (a) Be, (b) BeH and (c) BeH2 through coronene. The total barriers are decomposed into the deformation energy Edef accounting for geometrical changes in the coronene molecule and the rest energy ΔE according to Eq. (2). The latter contribution is denoted simply as “difference” in the figure. (For interpretation of the references to color in the text, the reader is referred to the web version of the article.)
Mentions: In Fig. 3, we depict the energy barriers for permeation of (a) Be, (b) BeH and (c) BeH2 through the center of coronene (black lines augmented with circles). For simplicity, we plot only the barriers obtained at the PBE0/3-21G level of theory (solid lines) as the curves obtained at the B3LYP/6-31G level of theory yield generally very similar results. In Fig. 3(b), however, we show also the data obtained with B3LYP/6-31G as for the PBE0/3-21G calculations beyond z = 1.2 Å no SCF-convergence could be achieved.

Bottom Line: We compare the energy barriers encountered by these molecular projectiles with the ones that are obtained for atomic H, Be, C and O.Furthermore, for some of the species fragmentation is observed.Implications with respect to plasma-surface interaction are discussed.

View Article: PubMed Central - PubMed

Affiliation: Institute of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.

ABSTRACT

We performed density functional theory calculations to explore the energetic and geometric aspects of the permeation of H2, BeH x , OH x (x = 1, 2) and CH y (y = 1-4) through the central hexagon of coronene. Coronene serves as a cluster model for extended graphene which can be regarded as the first layer of a graphite (0 0 0 1) surface. We compare the energy barriers encountered by these molecular projectiles with the ones that are obtained for atomic H, Be, C and O. The barriers are substantially lower if projectiles possess free valences that can bind to the carbon entity. Furthermore, for some of the species fragmentation is observed. Implications with respect to plasma-surface interaction are discussed.

No MeSH data available.


Related in: MedlinePlus