An%20approximate%20DFT-method%20to%20understand%20complex%20materials%20structures,%20properties%20and%20functions

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An approximate DFT-method to understand complex
materials structures, properties and functions
historical sketch multi-scale perspectives
recent applications future challenges
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An approximate DFT-method to understand complex
materials structures, properties and functions
History of DFTB goes back to 1986 ? Seifert,
Eschrig, Bieger, Zeitschr.physikal.Chemie
(Leipzig) 267, 529 Eine
Approximate Variante der LCAO-X?-Methode
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An approximate DFT-method to understand complex
materials structures, properties and functions
History of DFTB goes back to 1986 ? Seifert,
Eschrig, Bieger, Zeitschr.physikal.Chemie
(Leipzig) 267, 529 Eine
Approximate Variante der LCAO-X?-Methode
Diamond nucleation
Novel SiCN-ceramics
Si cluster growth Koblar Jackson
DiCarlo, Pecchia Rom Molecular Electronics
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Hierarchy of methods for real materials
simulations
Continuum theory Thermodynamics
classical Force fields MM
Physics Chemistry Biology Engineering
Semp.QC TB
Ab initio DFT/QC
Length scale
nm
?m
mm
m
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Two major strategies for multi-scale approaches
Continuum theory Thermodynamics
Hierarchical validation
classical Force fields MM
Physics Chemistry Biology Engineering
Semp.QC TB
BCCMS DFTB
Coupling by direct interfacing
Ab initio DFT/QC
Length scale
nm
?m
mm
m
6
Hierarchy of methods for real materials
simulations
Continuum theory Thermodynamics
classical Force fields MM
Physics Chemistry Biology Engineering
Semp.QC TB
BCCMS DFTB
Ab initio DFT/QC
Length scale
nm
?m
mm
m
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Approximate density-functional theoryPorezag-Phys
.Rev.B 51,12947(95), Elstner-Phys.Rev.B
58,7260(98), Frauenheim-.J.Phys.C14,3015(02)-Seife
rt
Density-Functional-based Tight-Binding DFTB
Ho?? - non-scc talk by G.Seifert
H?? - scc-DFTB talk by M.Elstner
Handshaking with large set of experimental data
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MD Simulation after 1keV atom subplantation
thermal spike rapid quenching of ta-C at 3.3
g/cm3
Cooling by velocity rescale
Growth by atom bombard
500-1000 atoms routinely on WSs
Atom trajectories classically in fs-time steps
with quantum mechanical interatomic forces
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High-density amorphous carbon films, 3.0 3.5
g/cm3
One application
Subplantation growth with energetic CH-radicals
or C-atoms (10 km/sec) sp2sp3 1486
C256H86 3.0g/cm3 Seggregation of amorphous
diamond clusters embedded in sp2/sp3 a-CH
matrix
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Spontaneous nucleation of diamond in high-density
ta-C(H)
Subplantation growth with energetic C-atoms (10
km/sec) sp2sp3 1486
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Spontaneous formation of diamond under BEN
conditionsBias Enhanced Nucleation
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Spontaneous formation of diamond under BEN
conditionsBias Enhanced Nucleation
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Advanced functionality of DFTB for open shell
systems Christof Köhler et al. Physical
Chemistry Chemical Physics, 3 (2001) 5109-5114.
S-DFTB C.Köhler-talk
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Recently more new advanced functions in
DFTBElectronic ground state ? Excited state
systems T.Niehaus et al. Phys.Rev.B 63, 085105
(01)
S-DFTB C.Köhler-talk
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Largest dynamical simulation of excited state
system Optical adsorption studies
Order-N LDM-formalism time-domaine T.Niehaus,
G.H.Chen, to be published
S-DFTB
Optical absorption spectra 864 H2O - cluster O(N)
LDM-TDDFTB
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Recently more new advanced functions in
DFTBLaser-matter interaction B.Torralva et al.,
PRB64, 153105 (01) T.Niehaus et al. Eur.Phys.J.
D, 35,467(05)
S-DFTB C.Köhler-talk
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Recently more new advanced functions in
DFTBLaser-matter interaction B.Torralva et al.,
PRB64, 153105 (01) T.Niehaus et al. Eur.Phys.J.
D, 35,467(05)
9,5 mJ/cm2
S-DFTB C.Köhler-talk
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Quantum transport on the molecular scaleDiCarlo,
A.Gagliardi, A.Pecchia, T.Niehaus, TF ?
www.quantrans.org
S-DFTB C.Köhler-talk
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Additional advanced functions in DFTB
Linear scaling W.Yang-talk
LDAU B.Hourhine-talk
GW/BSE-DFTB T.Niehaus-talk
QM/MM M.Elstner, Q.Cui, J.Hermans talks
S-DFTB C.Köhler-talk
QM/QM CPMD T.Heine-talk
R-DFTB H.Vitek-talk
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Additional advanced functions in DFTB
Linear scaling W.Yang-talk
LDAU B.Hourhine-talk
GW/BSE-DFTB T.Niehaus-talk
QM/MM M.Elstner, Q.Cui, J.Hermans talks
S-DFTB C.Köhler-talk
New release of DFTB talk by Balint
Aradi www.dftb.org
QM/QM T.Heine-talk
R-DFTB H.Vitek-talk
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Two major strategies for multi-scale approaches
Continuum theory Thermodynamics
Hierarchical validation
classical Force fields MM
Physics Chemistry Biology Engineering
Semp.QC TB
BCCMS DFTB
Coupling by direct interfacing
Ab initio DFT/QC
Length scale
nm
?m
mm
m
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Two major strategies for multi-scale approaches
Continuum theory Thermodynamics
Wetting of surfaces
classical Force fields MM
Physics Chemistry Biology Engineering
Semp.QC TB
BCCMS DFTB
Coupling by direct interfacing
Ab initio DFT/QC
Length scale
nm
?m
mm
m
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Two major strategies for multi-scale approaches
Continuum theory Thermodynamics
Wetting of surfaces
classical Force fields MM
Physics Chemistry Biology Engineering
Semp.QC TB
BCCMS DFTB
Biomolecular functions
Ab initio DFT/QC
Length scale
nm
?m
mm
m
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Hierarchical validation for multi-scale approaches
1-st strategy
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Functionalization of substrates for designing
materials properties
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NANOFUNK ? Nanofunctionalization of materials
substratesChristof Köhler
Siliconnitrid-ceramics (Cerobaer), with CFx
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Nanofunctionalization of SiO2 substrate by CFx
plasma depositionChristof Köhler
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Wetting on an idealized isotropic graphite
substrate
MM-FF (DFTB) ? H-bonds/vdWaals Monte-Carlo
sampling 36000 cycles
start
final
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Wetting ? PE and PTFE continued
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Hydrophilic wetting on hydroxylated SiO2 substrate
clean reconstructed surface in 10 Å height 90o
Hydroxylated surface in 14.5 Å height 65o
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Hydrophobic conversion of SiO2 by CF3
functionalization
All recent results C. Köhler to be published
Hydroxilated SiO2 is hydrophilic How we can
reverse it hydrophobic ?
Control of wetting by
chemical substitution and mechanical disorder ?
variation of roughness
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Scanning of reaction barriers for polymer
adsorption on Al2O3 NEB J. Knaup, et al.
submitted to J.Phys.Chem.B (June 2006)
Formation of hybrid-polymer-solid interfaces
BCCMS
FhG-IFAM
Idealized model-type simulation rather than
simulation under technical relevant conditions
taking into account the real physiologic
environment
QM/MM(GROMOS)-implementation for similar studies
in solvents/neighbouring molecules
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Two major strategies for multi-scale approaches
Continuum theory Thermodynamics
Wetting of surfaces
classical Force fields MM
Physics Chemistry Biology Engineering
Semp.QC TB
BCCMS DFTB
Biomolecular functions
Ab initio DFT/QC
Length scale
nm
?m
mm
m
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Direct interfacing of methods for multi-scale
approaches
2-nd strategy
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MM-MD study of water transport through aquaporine
membranes forced by osmotic pressure
The family of aquaporins conduct water and other
small, uncharged molecules. Responsible for
homeostasis in cells, present in almost every
organism - plants, animals Involved in multiple
human illnesses In contrast to other membrane
spanning channels (e.g., gramicidin), aquaporins
do not transport charged species, Why ?
2003
Discovered by Peter Agre by serendipy 1988
Helmut Grubmüller, MPI-Göttingen
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Why aquaporine membranes block proton transport
? M.Hoffmann, P.König, E.Takhorshid, K.Schulten,
T.F.
Aquaporins support a line of water molecules
through the pore allowing passage of
water Structure - spatial or orientational
disruption versus Electrostatics - desolvation or
protein
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Potential of Mean Force PMF-calculation
Aquaporins support a line of water molecules
through the pore allowing passage of
water Structure - spatial or orientational
disruption versus Electrostatics - desolvation or
protein
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Potential of Mean Force PMF-calculation
Aquaporins support a line of water molecules
through the pore allowing passage of
water Structure - spatial or orientational
disruption versus Electrostatics - desolvation or
protein
Perturbation analysis clarifies the contributions
of different structural and electrostatical
elements
??? What really prevents proton transport ???
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QM/MM/Continuum Multiscaling approach by direct
interfacing
QM chemical reactive bond formation/dissociation
MM constraints and conformational sampling in
protein environment and solution GSBP - continuum
electrostatics for heterogeneous protein,
solvent, lipid environment
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Light is used throughout the biosphere as energy
and information source
Color tuning of rhodopsins Talk by Marius Wanko
DFTBOM2
Proton transport in bR Talk by Nicoleta Bondar
DFG-FOG 490 bR and Rh
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Major demands ? industrial relevant
projectswhich address reactive processes on the
nano-size scale
Summary !
Simple QM-method efficient, accurate and
transferable chemistry
Lesekopf
Future challenges in materials simulations
Large system sizes (?m) and extended sampling (ms)
Model-like simulationen ? treatment of
physiological environment chemical reactive
processes on nano-scale ? corrosion, fatigue
behavior of materials
Increasing complexity of materials
systems/combinations ? QM Hybrid materials
bio-organic-inorganic
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Interdisciplinary research team at Paderborn
University
Expertise of ? Physics Chemistry Biology
Engineering Science
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From 1-st of April 2006 ? move to University of
Bremen
Bremen Center for Computational Material
Sciencesupported by DFG, DAAD, VW, EC, BMBF,
FhG, Humboldt
Expertise of ? Physics Chemistry Biology
Engineering Science
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Thank you for your interest and patience
sunset at the North Pole with the moon at its
closest point
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Needs to be achieved for technological relevant
materials simulations Multiscale hirarchy of
simulation strategies under environmental load
conditions
Time/fatique
Continuum mechanics Electrostatics Microstructure
Finite elements FEM Environment/Constraints
Statistical sampling stochastic theory
Config.sampling Thermodynamic Potentials Rate
equations Kinetic Monte-Carlo
Classical atomistics Force fields MM
Coarse Graining FEM
ns/ps
days/years
Quantum atomistics Reactive chemistry Electrochemi
cal environment
Hirarchical validation direct interfacing
Length scale
nm
?m
mm
m
Validation by experimental testing
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Quantum transport on the molecular scale DFG-SPP
1243 www.quantrans.org
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Molecular Electronics
Molecular electronics ? further reduction cost,
size and switching time
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DFTB - Nonequilibrium Green function approach for
transportA. Pecchia, A. DiCarlo, et al Lecture
Notes in Physics, Springer
tLM
tRM
HM
HL
HR
-?
?
Molecular region
Left Contact
Right Contact
Applied bias at open boundary conditions Bias
drop through molecular junction SCF in charge
density Electron-phonon coupling ?
dissipation ee, eph elastic and inelastic
scattering Beyond DFT ? quasiparticle correction
GW
gDFTB http//icode.eln.uniroma2.it
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SCF-NEGF transport with electron-phonon coupling
in alkenothiols
A. Pecchia et al., Nano Letters 4, 2125 (2004)
G. Solomon et al., J. Chem Phys 124, 094704 (2006)
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Inelastic Electron Tunneling Spectroscopy
inelastic electron-phonon scattering
Low temperature
Elastic
eV
h?
Inelastic
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IETS experiments ? features of molecule contact
geometries
W. Wang, T. Lee, I. Kretzschmar M. Reed Nano
Lett. (2004) 4(4) 643-646
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Inelastic Electron Tunneling Spectroscopy
Solomon, Gagliardi, Pecchia, T.F. et al J. Chem
Phys 124, 094704 (2006)
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Thank you for your interest and patience