ab initio investigation of c 2 h 2 -x van der waals complexes (x=ar,kr, xe) c. lauzin, e. cauët, j....
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AB INITIO INVESTIGATION OF C2H2-X VAN DER WAALS COMPLEXES (X=Ar,Kr, Xe)
C. Lauzin, E. Cauët, J. Demaison, J. Liévin
Chimie quantique et Photophysique
Université Libre de Bruxelles
Introduction
Solve numericallythis problem
GET RELIABLE INTERMOLECULAR POTENTIAL
FOR C2H2-Ar*,Kr, Xe
C2H2-Ar and C2H2-Kr absorption spectrum
n1+ n3
Lauzin et al , J.Phys.Chem A,1113 (2009) 2361
*Munteanu et al, J. Chem. Phys, 123 (2005) 14309
• Distributed polarisabilities
• Ab initio calculations
• Results
• Conclusion
Summary
q
R
Distributed PolarisabilitiesZ. Kisiel, J. Phys. Chem, 95 (1991) 7605
Rgdim software
AttractionRepulsion
Dispersion
25*[1 tanh{( 0.6) / 0.1}]ij ijR Repulsionij =
http://www.ifpan.edu.pl/~kisiel/prospe.htm
)(2
36ij
jiijdisp R
attraction
3.764.364.94
Distributed PolarisabilitiesRdim =
Inte
racti
on e
nerg
y (c
m-1
)
3.764.364.94
5.08 4.51 3.90
Distributed PolarisabilitiesRdim =
Inte
racti
on e
nerg
y (c
m-1
)
3.764.364.94
5.08 4.51 3.90
Distributed Polarisabilities
SIMILAR
LONGER DISTANCE
TWO MINIMA
Inte
racti
on e
nerg
y (c
m-1
)
3.764.364.94
5.08 4.51 3.90
Distributed PolarisabilitiesRdim =
Inte
racti
on e
nerg
y (c
m-1
)
Ab initio computational methods
Electron Correlation
Ab initio computational methods
Ab initio computational methods
Electron Correlation
CCSD(T)
Relativistic effect
Ab initio computational methods
Electron Correlation
CCSD(T)
Relativistic effect
Douglas-Kroll correction
Relativistic ECP
Ab initio computational methods
Electron Correlation
CCSD(T)
Relativistic effect
Douglas-Kroll correction
Relativistic ECP
Interaction energy (cm-1)
Size of the basis
Ab initio computational methods
Electron Correlation
CCSD(T)
Slow convergence
With the basis aug-cc-pVXZ
X=T,Q,5 noted “AVXZ”
Slow convergence
Relativistic effect
Douglas-Kroll correction
Relativistic ECP
MIDBOND
Ab initio computational methods
Electron Correlation
CCSD(T)
Computational Methodology
Slow convergence
Relativistic effect
Douglas-Kroll correction
Relativistic ECP
MIDBOND
ACCURACY?Electron Correlation
CCSD(T)
Ab initio calculations C2H2-Kr 4.1 Å and 60° Counterpoise corrected
Abbreviations:DK=Douglas-KrollECP=electron core potentialBondf= bond function CBS= complete basis set
1. RELATIVISTIC EFFECT 4.1 Å and 60°Counterpoise corrected
Ab initio calculations C2H2-Kr
Abbreviations:DK=Douglas-KrollECP=electron core potentialBondf= bond function CBS= complete basis set
4.1 Å and 60°1. RELATIVISTIC EFFECT Counterpoise corrected
Ab initio calculations C2H2-Kr
Abbreviations:DK=Douglas-KrollECP=electron core potentialBondf= bond function CBS= complete basis set
4.1 Å and 60°2. Convergence Counterpoise corrected
Ab initio calculations C2H2-Kr
Abbreviations:DK=Douglas-KrollECP=electron core potentialBondf= bond function CBS= complete basis set
4.1 Å and 60°3. Convergence + relativistic Counterpoise corrected
Ab initio calculations C2H2-Kr
Abbreviations:DK=Douglas-KrollECP=electron core potentialBondf= bond function CBS= complete basis set
4.1 Å and 60°3. Convergence + relativistic Counterpoise corrected
Ab initio calculations C2H2-Kr
Abbreviations:DK=Douglas-KrollECP=electron core potentialBondf= bond function CBS= complete basis set
4.1 Å and 60°4. Extrapolation accuracy? Counterpoise corrected
Ab initio calculations C2H2-Kr
Abbreviations:DK=Douglas-KrollECP=electron core potentialBondf= bond function CBS= complete basis set
4.1 Å and 60°4. Extrapolation accuracy? Counterpoise corrected
CBS AVXZ-ECP
Ab initio calculations C2H2-Kr
Abbreviations:DK=Douglas-KrollECP=electron core potentialBondf= bond function CBS= complete basis set
2 cm-1
4.1 Å and 60°5. Make a choice!! Counterpoise corrected
CBS AVXZ-ECP
Ab initio calculations C2H2-Kr
Abbreviations:DK=Douglas-KrollECP=electron core potentialBondf= bond function CBS= complete basis set
2 cm-1
RESULTS C2H2-Kr!!!!!
q
R dimer
q
C2H2-Kr
RESULTS C2H2-Kr!!!!!
q
R dimer
q
C2H2-KrTwo minima 1) Local: Linear2) Global: skew T-shaped
Global minimum:R= 4.07 Å=64.9q
Is the geometry correct?
Interaction energy (cm-1)
Ab initio simulation:Same constants for ground and excited states
EXPERIMENTALSPECTRUM
RESULTS C2H2-Kr!!!!!
Is the geometry correct?
PGOPHER SOFTWARE (COLIN WESTERN)
AB INITIO ROTATIONAL CONSTANTS
Ab initio simulation:Same constants for ground and excited states
EXPERIMENTALSPECTRUM
RESULTS C2H2-Kr!!!!!
Is the geometry correct?
PGOPHER SOFTWARE (COLIN WESTERN)
Comparison
Surface C2H2 Ar
Ar Kr Xe
R 3.99* 4.07 4.23
q 60.6°* 64.9° 68.5
Interaction energy(cm-1)
-122.17* -150.36 -175.80
*Munteanu et al, J. Chem. Phys, 123 (2005) 14309
• Distributed polarisabilities provide a good qualitative topology of the intermolecular PES
• Relativistic ECP reproduce well the Douglass Kroll all-electrons calculations.
• Mid bond functions Improve drastically the convergence to CBS.
Conclusion
• Michel Herman• Keevin Didriche• Sonia Melandri• Maxence Delsaut• FNRS • ULB• Colin Western• M. Kisiel
• And you for your attention…
Acknowledgments