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Interaction of Beryllium Atoms, Dimers and Ben clusters with Graphite
A theoretical approach based on DFT
Y. Ferro, N. Fernandez, and A. Allouche
Physique des Interactions Ioniques et Moléculaires CNRS/Université de Provence (UMR 6633), Marseille, France
Max-Planck-Institut für Plasmaphysik, Garching b. München, Germany
Ch. Linsmeier
ICTP-IAEA Workshop 23-27 Jan 2012
General objective:
• the formation of mixed Be/C materials in ITER
• how beryllium modify the basic electronic properties of graphite
• the impact on the chemical reactivity of the material
OBJECTIVE
Objective of the present work:
• a single atom of beryllium
• a beryllium dimer
• larger beryllium clusters
We investigated the interaction of :
At the surface and in the bulk of graphite
ICTP-IAEA Workshop 23-27 Jan 2012
METHOD
Density Functional Theory
Planes waves with Ultra-Soft pseudo potentials
Quantum Espresso Package
Perdew Burke and Ernzerhof exchange and correlation Functional
Van der Waals interaction: Grimme D2 correction
Post Hartree-Fock
Help to validate the choice of the functional
Small molecular systems (ethylen, benzene and pyrene molecules)
Single-determinent methods: MP2, CCSD(T)
Multi-references: CASSCF, CASPT2
ICTP-IAEA Workshop 23-27 Jan 2012
Be Dimer on the Surface
Eads = -1.770 eV
Equilibrium geometry at adsorption in the perpendicular configuration
• No magnetic state
• Be2 bind through sp2 hybrids orbitals formed from 2s, 2py, 2pz
Eads = -1.258 eV
Equilibrium geometry at adsorption in the parallel configuration
0 2 4 6 8
10 12 14
-10
-50
510
pD
OS
pi
pDOS piEsca
le
d
E(eV)
1e1(1pu)
C6(D¥h) EF
-10
0
-8
-6
-4
-2
2a(1su)
1a(1sg)
Be2 Graphene
2a
3a
pA1
1a
An e leave from s* of Be2 to the conduction band of gaaphite
Orbital mixing 2s-2pz bonding of Be2 to the surface
• magnetization of 1mB localized on the farthest Be from the surface
Parallel Configuration
Perpendicular Configuration
strengthening of Be-Be bond
ICTP-IAEA Workshop 23-27 Jan 2012
See you later
ICTP-IAEA Workshop 23-27 Jan 2012
