CC C6 (vdW) coefficients

 Posts: 1
 Joined: 02 Nov 2014, 15:10
 First name(s): Luuk
 Last name(s): Visscher
 Affiliation: VU Amsterdam
 Country: Netherlands
CC C6 (vdW) coefficients
Dear Dalton community,
I'd like to use the CC response code to get vanderWaals dispersion coefficients for atoms. I can see I can do this in the **RESPONSE section, but this only allows HF, DFT and CI. For consistency with other calculations, I would like to do this with the separate CC response module. Can this one handle imaginary frequencies (which is needed for this) ? And if, so which would be the keywords to look up ?
thanks for your help,
Luuk
I'd like to use the CC response code to get vanderWaals dispersion coefficients for atoms. I can see I can do this in the **RESPONSE section, but this only allows HF, DFT and CI. For consistency with other calculations, I would like to do this with the separate CC response module. Can this one handle imaginary frequencies (which is needed for this) ? And if, so which would be the keywords to look up ?
thanks for your help,
Luuk

 Posts: 87
 Joined: 06 Sep 2013, 13:49
 First name(s): Sonia
 Last name(s): Coriani
 Affiliation: DTU Chemistry
 Country: Denmark
Re: CC C6 (vdW) coefficients
Dear Luuk,
we already talked about it directly, but I am posting this for the benefit of the Dalton community.
One way would be to use the same strategy as used in the analytic implementation of the dispersion coefficients of the
polarisability (J. Chem. Phys., Vol. 107, 1997, 10592).
The Cauchy moments are obtained adding the
.DISPCF
10 (or whatever order you want)
to the *CCLR section relative to a polarisability calculation.
Another way could be to use the Lanczos implementation of the complex polarisability presented in
dx.doi.org/10.1021/ct200919e  J. Chem. Theory Comput. 2012, 8, 1616−1628.
All the best
Sonia
we already talked about it directly, but I am posting this for the benefit of the Dalton community.
One way would be to use the same strategy as used in the analytic implementation of the dispersion coefficients of the
polarisability (J. Chem. Phys., Vol. 107, 1997, 10592).
The Cauchy moments are obtained adding the
.DISPCF
10 (or whatever order you want)
to the *CCLR section relative to a polarisability calculation.
Another way could be to use the Lanczos implementation of the complex polarisability presented in
dx.doi.org/10.1021/ct200919e  J. Chem. Theory Comput. 2012, 8, 1616−1628.
All the best
Sonia

 Posts: 4
 Joined: 12 Sep 2014, 05:11
 First name(s): Yixin
 Last name(s): Zheng
 Affiliation: UTAustin
 Country: United States
Re: CC C6 (vdW) coefficients
Dear Sonia,
Thank you for posting this. I am wondering if Dalton can calculate imaginary part of polarizability with respect to photon energy.
I want to plot this spectrum in order to compare with other methods. It seems that Cauchy moments can only provide correct imaginary spectrum below the first pole.
In this paper "Lanczos implementation of the complex polarisability", the approximation like a plasmonpole is used to get the spectrum (Fig.7).
I am wondering if there is a sort of "ab initio" way so that I can calculate this imaginary response for each frequency.
Best,
Yixin
Thank you for posting this. I am wondering if Dalton can calculate imaginary part of polarizability with respect to photon energy.
I want to plot this spectrum in order to compare with other methods. It seems that Cauchy moments can only provide correct imaginary spectrum below the first pole.
In this paper "Lanczos implementation of the complex polarisability", the approximation like a plasmonpole is used to get the spectrum (Fig.7).
I am wondering if there is a sort of "ab initio" way so that I can calculate this imaginary response for each frequency.
Best,
Yixin

 Posts: 87
 Joined: 06 Sep 2013, 13:49
 First name(s): Sonia
 Last name(s): Coriani
 Affiliation: DTU Chemistry
 Country: Denmark
Re: CC C6 (vdW) coefficients
Dear Yixin,
To be 100% sure I understood you:
Do you want to compute the absorption spectrum directly from the imaginary polarizability computed at different (real) frequencies?
At which level of theory?
All the best
Sonia
To be 100% sure I understood you:
Do you want to compute the absorption spectrum directly from the imaginary polarizability computed at different (real) frequencies?
At which level of theory?
All the best
Sonia

 Posts: 4
 Joined: 12 Sep 2014, 05:11
 First name(s): Yixin
 Last name(s): Zheng
 Affiliation: UTAustin
 Country: United States
Re: CC C6 (vdW) coefficients
Dear Sonia,
Thank you for your reply. I don't need to calculate the absorption. What I need is to calculate the polarizability (\alpha) with respect to imaginary frequency \alpha( i \omega). I am wondering if I can use Dalton to calculate this spectrum in order to compare with spectrums calculated by other methods (like using a model for polarizability).
Now, I only know how to calculate the polarizability with respect to real frequency \alpha( \omega ). But this transformation between real frequency and imaginary frequency seems to be nontrivial.
Since I want to compare with other methods, it will be perfect to have this spectrum at relatively high accuracy level, like CCSD. But I am not sure if this is possible right now.
Best,
Yixin
Thank you for your reply. I don't need to calculate the absorption. What I need is to calculate the polarizability (\alpha) with respect to imaginary frequency \alpha( i \omega). I am wondering if I can use Dalton to calculate this spectrum in order to compare with spectrums calculated by other methods (like using a model for polarizability).
Now, I only know how to calculate the polarizability with respect to real frequency \alpha( \omega ). But this transformation between real frequency and imaginary frequency seems to be nontrivial.
Since I want to compare with other methods, it will be perfect to have this spectrum at relatively high accuracy level, like CCSD. But I am not sure if this is possible right now.
Best,
Yixin

 Posts: 116
 Joined: 27 Aug 2013, 16:38
 First name(s): Joanna
 Last name(s): Kauczor
 Affiliation: Helsinki
 Country: Finland
Re: CC C6 (vdW) coefficients
Dear Yixin,
what you are asking for is available 'explicitly' at HF, DFT and MCSCF level of theory.
More details you can find in the manual, chapter about **RESPONSE, section *ABSORP
All the best,
Joanna
what you are asking for is available 'explicitly' at HF, DFT and MCSCF level of theory.
More details you can find in the manual, chapter about **RESPONSE, section *ABSORP
All the best,
Joanna

 Posts: 5
 Joined: 17 Nov 2014, 12:23
 First name(s): Tiago
 Middle name(s): Quevedo
 Last name(s): Teodoro
 Affiliation: University of Sao Paulo
 Country: Brazil
Re: CC C6 (vdW) coefficients
Dear Dalton experts,
The C6 coefficient for the Ne2 dimer that I get from the following output is totally different from what is found on literature (e.g., around 6.4 from Hattig, Christiansen, and Jorgensen, J. Chem. Phys, 107, 1997). I tried different CC methods and basis sets, results are similar.
What is missing?
Content of the .dal input file

**DALTON INPUT
.RUN WAVE FUNCTIONS
**INTEGRALS
.DIPLEN
**WAVE FUNCTIONS
.CC
*CC INPUT
.CCSD
*CCLR
.OPERATOR
ZDIPLEN ZDIPLEN
.DISPCF
10
**END OF DALTON INPUT
Content of the .mol file

BASIS
augccpCV5Z
Neonium dimer
using the augccpCV5Z basis
Atomtypes=1
Charge=10.0 Atoms=2
Ne 0.0 0.0 0.000
Ne 0.0 0.0 6.630
Output:
A operator B operator n D_AB

ZDIPLEN ZDIPLEN 4 41248.6877579
2 20.0385938177
0 5.38230818615
2 5.63794974443
4 9.46851069558
6 19.6218654445
8 44.4048295907
10 103.959739247
The C6 coefficient for the Ne2 dimer that I get from the following output is totally different from what is found on literature (e.g., around 6.4 from Hattig, Christiansen, and Jorgensen, J. Chem. Phys, 107, 1997). I tried different CC methods and basis sets, results are similar.
What is missing?
Content of the .dal input file

**DALTON INPUT
.RUN WAVE FUNCTIONS
**INTEGRALS
.DIPLEN
**WAVE FUNCTIONS
.CC
*CC INPUT
.CCSD
*CCLR
.OPERATOR
ZDIPLEN ZDIPLEN
.DISPCF
10
**END OF DALTON INPUT
Content of the .mol file

BASIS
augccpCV5Z
Neonium dimer
using the augccpCV5Z basis
Atomtypes=1
Charge=10.0 Atoms=2
Ne 0.0 0.0 0.000
Ne 0.0 0.0 6.630
Output:
A operator B operator n D_AB

ZDIPLEN ZDIPLEN 4 41248.6877579
2 20.0385938177
0 5.38230818615
2 5.63794974443
4 9.46851069558
6 19.6218654445
8 44.4048295907
10 103.959739247
 Attachments

 2coeff_ne2_ap5z.out
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 Posts: 7
 Joined: 15 Nov 2013, 11:46
 First name(s): Michal
 Last name(s): Jaszunski
 Affiliation: ICHO PAN
 Country: Poland
Re: CC C6 (vdW) coefficients
hello,
as I understand, the recent versions of Dalton work more or less automatically with the proper
input data, providing C6 and/or, as a byproduct, the needed imaginary frequency polarisabilities,
but some comments on the old techniques that apparently have been forgotten may be useful:
if you want the coefficient for the NeNe interaction, you need to run the calculation for the
Ne atom  not for the dimer at any geometry (that, I believe, has to be so even now...).
In the output shown you get the coefficients of the Cauchy expansion for the atom, which enables
you to compute the real and imaginary polarisabilities at any frequency (but note: you need to use some
analytic continuation of the series, e.g. Pade approximants; it is only asymptotically convergent
beyond the first pole). These enable you to get via the following integration the C6. If you want
the C6 coefficient for e.g. HeNe interaction you integrate the product of He and Ne imaginary
polarisabilities etc.
Moreover (commenting on some older questions) the same technique may be applied to get many
other interaction coefficients, e.g for quadrupolar interactions or interactioninduced hyperpolarisabilities;
I am not sure that these are so easily available in a more automatic manner.
regards,
Michal
as I understand, the recent versions of Dalton work more or less automatically with the proper
input data, providing C6 and/or, as a byproduct, the needed imaginary frequency polarisabilities,
but some comments on the old techniques that apparently have been forgotten may be useful:
if you want the coefficient for the NeNe interaction, you need to run the calculation for the
Ne atom  not for the dimer at any geometry (that, I believe, has to be so even now...).
In the output shown you get the coefficients of the Cauchy expansion for the atom, which enables
you to compute the real and imaginary polarisabilities at any frequency (but note: you need to use some
analytic continuation of the series, e.g. Pade approximants; it is only asymptotically convergent
beyond the first pole). These enable you to get via the following integration the C6. If you want
the C6 coefficient for e.g. HeNe interaction you integrate the product of He and Ne imaginary
polarisabilities etc.
Moreover (commenting on some older questions) the same technique may be applied to get many
other interaction coefficients, e.g for quadrupolar interactions or interactioninduced hyperpolarisabilities;
I am not sure that these are so easily available in a more automatic manner.
regards,
Michal

 Posts: 87
 Joined: 06 Sep 2013, 13:49
 First name(s): Sonia
 Last name(s): Coriani
 Affiliation: DTU Chemistry
 Country: Denmark
Re: CC C6 (vdW) coefficients
Dear Tiago,
Michal is right, and I apologize if my message was misunderstood.
As I wrote, one can use the same _strategy_ described in J. Chem. Phys., Vol. 107, 1997, 10592,
i.e. compute the Cauchy moments for the atom(s), apply Pade approximants and integrate.
Regards
Sonia
Michal is right, and I apologize if my message was misunderstood.
As I wrote, one can use the same _strategy_ described in J. Chem. Phys., Vol. 107, 1997, 10592,
i.e. compute the Cauchy moments for the atom(s), apply Pade approximants and integrate.
Regards
Sonia

 Posts: 5
 Joined: 17 Nov 2014, 12:23
 First name(s): Tiago
 Middle name(s): Quevedo
 Last name(s): Teodoro
 Affiliation: University of Sao Paulo
 Country: Brazil
Re: CC C6 (vdW) coefficients
Dear Sonia and Michal,
Thank you for the clarification.
Best wishes,
Tiago
Thank you for the clarification.
Best wishes,
Tiago
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