p.m. dinh, e. suraud
DESCRIPTION
Time-Dependent Density Functional Theory in metal clusters. P.M. Dinh, E. Suraud. Laboratoire de Physique Théorique (Toulouse). P.G. Reinhard, F. Fehrer. Institut für Theoretische Physik (Erlangen). Outline. Nuclei vs. metal clusters DFT in metal clusters A cluster@substrate model - PowerPoint PPT PresentationTRANSCRIPT
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
P.M. Dinh, E. SuraudLaboratoire de Physique Théorique (Toulouse)
P.G. Reinhard, F. FehrerInstitut für Theoretische Physik (Erlangen)
Time-Dependent Density Functional Theory
in metal clusters
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
• Nuclei vs. metal clusters
• DFT in metal clusters
• A cluster@substrate model
• Deposition of Na cluster on Ar surface
• Conclusion and perspectives
Outline
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
Nuclei Metal clusters
relevant length scale
R ~~ r0 N 1/3
Nuclei vs. Metal clusters
N < 300 nucleons 3 < N < 105-7 atomsR ~~ rs N 1/3
dense systemswith strong Pauli
quantummean field
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
MEAN
FIELD
... 8250282082
Short range (nuclear) + long range (Coulomb) interactions
Long range (Coulomb) interactions
Nuclei vs. Metal clusters
Free nucleons Nucleons IN nucleus Nucleus
Free atom Atom IN cluster Cluster
... 13892402082
Interactions
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
Nuclei vs. Metal clustersAlkalines
(Li, Na, K, Rb, Cs)
1 fs
100 fs
10 fs
Nuclei
10 fm/c
1000 fm/c
100 fm/c
Time scales
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
DFT in metal clustersValence electrons Ions = core electrons + atom
Degrees of freedom ?
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
3 groups : Dresden, Kyoto-Seattle, Erlangen-ToulouseSemi-classical versions (Grenoble, Erlangen-Toulouse)
DFT in metal clusters How to solve the problem?
« Exactly »Ab initio methods of quantum chemistryWave packets in molecular physicsBut very small systems
« Adiabatically»Born-Oppenheimer approximation= Electrons bound to ground state surfaceBut very weak excitations
« Effectively »Density Functional Theory (effective mean field )Level 1 : Electrons only (1984…) Shells, plasmon,…Level 2 : Electrons + ions (1994 …) Complete non-adiabatic treatment of electrons and ions
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
DFT in metal clusters
Hohenberg-Kohn (1964)for Coulomb system,GS energy = functional of
start from HF procedure
(local)
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
DFT in metal clusters ???
Local DensityApprox.
homogeneous electron gaz
Perdew, Wang(1992)
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
DFT in metal clusters
MD-TDDFT(LDA)
in LDA Adiab. LDA or TDLDA
non-adiab. dynamics(≠Born-Oppenheimer)
dynamics ?
IONS ?
TDDFT
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
TDDFT in metal clusters
Na9+ under laser irradiation
I = 5x1011 W/cm2
FWHM = 125 fs= 2.3 eVdelay = 50 fs
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
TDDFT in metal clusters
Calvayrac, Reinhard, Suraud (1998)
Na9+ Carbon chains
Optical response
exp.ab initio
TDLDA Yabana,Bertsch (1997)TDLDA Berkus,Reinhard,Suraud(2002)
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
A cluster@substrate modeleasier with embedded or deposited clusters
Na cluster + Ar substrate
DAr dynamically polarizable electron cloud
2 others classical d.o.f.
Need to model interaction with environment
DArRAr
Experiments...
RAr core
gaussians, width from ()
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
A cluster@substrate modelCoupling to valence electrons and ions
Coulombab initio
dipole-dipole
finalfine-tuning
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
Deposition of Na cluster on Ar surfaceBO surfaces
0,1-
0,05-
0
0,05
0,1
0,15
0,2
-7 -5 -3 -1 1 3 5 7 9Distance (a0)
Ener
gy (R
y)
Na@Ar384Na+@Ar384Na@383
Na and Na+@Ar384
Na @Ar383
surface
minimumin matrix !
a vacancy
atom
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
Deposition of Na cluster on Ar surfaceNa@Ar384
Ekin0 = 4.7 meV
mechanicalwave in matrix
atom
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
BO surfaces
0,1-
0,05-
0
0,05
0,1
0,15
0,2
-7 -5 -3 -1 1 3 5 7 9Distance (a0)
Ener
gy (R
y)
Na@Ar384Na+@Ar384Na@383
Deposition of Na cluster on Ar surfaceNa@Ar384
complex cross-overbetweenBO surfaces
contradiction with previous BO calculations ?Ekin0 = 4.7 meV
NO !≈ Na@Ar383
Na finally inside Ar matrix !
an Ar atom ejectedfrom firstlayer
atom
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
Deposition of Na cluster on Ar surfaceNa6@Ar87
Ekin0 = 2.2 meV
soft material
systematics on Ekin0 size of Na cluster size of Ar cluster deformation transfer of kin. E wave celerity ...
cluster
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
Conclusion
Other materials ... •In progress:
Ne, Kr substrates• In the future:
hard substrates (MgO, NaCl) water environment
Perspectives
• MD-TDLDA: powerful tool for metal clusters in agreement with experiments
• Interaction with polarizable Ar substrate quite cumbersome high computing-time very soft material
CNRS post-docsept/oct 2006
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
P.M.Dinh, Workshop ESNT, Jan. 23th 2006
DFT in metal clustersSelf-Interaction Correction
less expensive