Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[ticucubot]

Hi Alberto,

The manual of siesta-4.0.pdf did not address the issue on which pseudos 
should be used for vdW calculations. Are there practical details 
somewhere available or could you add some?


Thanks in advance

ticu


On 17.02.2016 12:36, Alberto Garcia wrote:

Hi,

There is a subtle point concerning the use of the pseudopotential approximation 
with van der Waals functionals. In short, since the vdW xc term
is non-local, the influence of the core can extend beyond the nominal 
"pseudopotential cutoff", leading to pseudos that can be pathological (for 
example, by converging to the coulomb tail too far out).

For this reason, pseudopotentials generated with van der Waals functionals are 
not recommended. Instead, we recommend to generate the pseudopotentials with a 
good GGA functional like PBE, optionally changing the exchange part by that of 
the vdW functional to be used.

This note will be added to the Siesta documentation as soon as possible.

  Best regards,

   Alberto


On 17 Feb 2016, at 00:56, I. Camps  wrote:


Hello Ticu,

You have to generate your own vdW-DFT pseudos.

What I did:
- Download any INP (LDA or GGA) file from the SIESTA pseudos database for your 
atoms,
- Change the head of the INP file and put the corresponding code for your 
desired flavor of vdW-DFT functional (the codes for each functional type and 
the place in the INP file you can find in the ATOM manual),
- Generate the pseudo using the ATOM program (comes with SIESTA and should be 
compiled separately with the same arch.file),
- Test the generated pseudo with the scripts that come with SIESTA.


[]'s,

Camps

On Tue, Feb 16, 2016 at 9:10 PM, ticu Cubot  wrote:
Hi Everybody!

Because the manual of newly released 4.0b-485 does not address this point, I 
would like to ask you: are the ABINIT pseudopotentials suitable for vdW-DFT 
calculations and, if so, which flavour (_lda, _gga)?

Many thanks,
ticu

Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[gagandeep Kaur]

Dear all
Kindly suggest what to do out of two options written below


%block XC.hybrid
2
GGA    revPBE   1   0
VDW   DRSLL    0   1
%endblock XC.hybrid

Or this?

XC.Functional                 VDW
XC.authors                      DRSLL

Sent from Samsung Mobile

 Original message From: "I. Camps" 
 Date:11/08/2016  7:13 PM  (GMT+05:30) 
To: siesta-l@uam.es Subject: Re: [SIESTA-L] A note of 
warning regarding pseudopotentials for vdW-DFT calculations 
Dear Seyed,

I have to agree with you. It is confusing.

If you get the manual (both SIESTA and ATOM) and read some tutorials, that´s 
the path (change the INP file, then test using the scripts).

With the email of Professor Alberto, I really do not now to match the two 
information.


[]'s,

Camps

On Thu, Aug 11, 2016 at 10:31 AM, Seyed Mohammad Tabatabaei  
wrote:
Dear Professor Camps,

I disagree with your statement and I refer to the message by Alberto Garcia:

"For this reason, pseudopotentials generated with van der Waals functionals are 
not recommended. Instead, we recommend to generate the pseudopotentials with a 
good GGA functional like PBE, optionally changing the exchange part by that of 
the vdW functional to be used." Alberto is certain about using PBE pseudos. One 
can even download them from the SIESTA website.

I just do not understand the meaning of "optionally changing the exchange part 
by that of the vdW functional to be used". Does it mean this?

%block XC.hybrid
2
GGArevPBE   1   0
VDW   DRSLL0   1
%endblock XC.hybrid

Or this?

XC.Functional VDW
XC.authors  DRSLL

Bests,



On Tue, Aug 9, 2016 at 5:52 PM, I. Camps  wrote:
Seyed,

I think that you just have to generate the vdW pseudo directly using ATOM. Only 
that.

Following the manual (ATOM 4.0.2 manual, page 13), you have the following 
flavors of vdW pseudos:

Van der Waals (VDW) density functionals, implemented as Rom´an-P´erez and Soler,
PRL 103, 096102 (2009):
∗ vw or vf: DRSLL (Dion et al, PRL 92, 246401 (2004))
∗ vl: LMKLL (Lee et al, PRB 82, 081101 (2010))
∗ vk: KBM (Klimes, Bowler, and Michaelides, JPCM 22, 022201 (2009))
∗ vc: C09 (Cooper, PRB 81, 161104 (2010))
∗ vb: BH (Berland and Hyldgaard, PRB 89, 035412 (2014))
∗ vv: VV (Vydrov and VanVoorhis, JCP 133, 244103 (2010)) 

[]'s,

Camps

On Tue, Aug 9, 2016 at 9:33 AM, Seyed Mohammad Tabatabaei  
wrote:
Dear all,

As I have understood, the DRSLL method for including the vdW interactions takes 
its correlation from the revPBE but the exchange part is innovated by the 
authors in the original DRSLL paper to include van der Waals interactions. Now, 
should I use PBE pseudos or should I use revPBE pseudos in my vdW calculations?

Bests,

Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[Anita Rani]

Please guide me
How to use these psf.in our fdf file
On 11 Aug 2016 19:10, "Seyed Mohammad Tabatabaei"  wrote:

> Sorry all SIESTERS,
>
> I want to apologize and correct my previous comment. The following is
> correct:
>
> The DRSLL method for including the vdW interactions takes its *exchange*
> from the revPBE but the *correlation* part is innovated by the authors in
> the original DRSLL paper to include van der Waals interactions.
>
>
>
> On Tue, Aug 9, 2016 at 5:03 PM, Seyed Mohammad Tabatabaei <
> smt...@gmail.com> wrote:
>
>> Dear all,
>>
>> As I have understood, the DRSLL method for including the vdW interactions
>> takes its correlation from the revPBE but the exchange part is innovated by
>> the authors in the original DRSLL paper to include van der Waals
>> interactions. Now, should I use PBE pseudos or should I use revPBE pseudos
>> in my vdW calculations?
>>
>> Bests,
>>
>
>

Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[I. Camps]

Dear Seyed,

I have to agree with you. It is confusing.

If you get the manual (both SIESTA and ATOM) and read some tutorials,
that´s the path (change the INP file, then test using the scripts).

With the email of Professor Alberto, I really do not now to match the two
information.


[]'s,

Camps

On Thu, Aug 11, 2016 at 10:31 AM, Seyed Mohammad Tabatabaei <
smt...@gmail.com> wrote:

> Dear Professor Camps,
>
> I disagree with your statement and I refer to the message by Alberto
> Garcia:
>
> "For this reason, pseudopotentials generated with van der Waals
> functionals are not recommended. Instead, we recommend to generate the
> pseudopotentials with a good GGA functional like PBE, optionally changing
> the exchange part by that of the vdW functional to be used." Alberto is
> certain about using PBE pseudos. One can even download them from the SIESTA
> website.
>
> I just do not understand the meaning of "optionally changing the exchange
> part by that of the vdW functional to be used". Does it mean this?
>
> %block XC.hybrid
> 2
> GGArevPBE   1   0
> VDW   DRSLL0   1
> %endblock XC.hybrid
>
> Or this?
>
> XC.Functional VDW
> XC.authors  DRSLL
>
> Bests,
>
>
>
> On Tue, Aug 9, 2016 at 5:52 PM, I. Camps  wrote:
>
>> Seyed,
>>
>> I think that you just have to generate the vdW pseudo directly using
>> ATOM. Only that.
>>
>> Following the manual (ATOM 4.0.2 manual, page 13), you have the following
>> flavors of vdW pseudos:
>>
>> Van der Waals (VDW) density functionals, implemented as Rom´an-P´erez and
>> Soler,
>> PRL 103, 096102 (2009):
>> ∗ vw or vf: DRSLL (Dion et al, PRL 92, 246401 (2004))
>> ∗ vl: LMKLL (Lee et al, PRB 82, 081101 (2010))
>> ∗ vk: KBM (Klimes, Bowler, and Michaelides, JPCM 22, 022201 (2009))
>> ∗ vc: C09 (Cooper, PRB 81, 161104 (2010))
>> ∗ vb: BH (Berland and Hyldgaard, PRB 89, 035412 (2014))
>> ∗ vv: VV (Vydrov and VanVoorhis, JCP 133, 244103 (2010))
>>
>> []'s,
>>
>> Camps
>>
>> On Tue, Aug 9, 2016 at 9:33 AM, Seyed Mohammad Tabatabaei <
>> smt...@gmail.com> wrote:
>>
>>> Dear all,
>>>
>>> As I have understood, the DRSLL method for including the vdW
>>> interactions takes its correlation from the revPBE but the exchange part is
>>> innovated by the authors in the original DRSLL paper to include van der
>>> Waals interactions. Now, should I use PBE pseudos or should I use revPBE
>>> pseudos in my vdW calculations?
>>>
>>> Bests,
>>>
>>
>>
>

Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[Seyed Mohammad Tabatabaei]

Dear Professor Camps,

I disagree with your statement and I refer to the message by Alberto Garcia:

"For this reason, pseudopotentials generated with van der Waals functionals
are not recommended. Instead, we recommend to generate the pseudopotentials
with a good GGA functional like PBE, optionally changing the exchange part
by that of the vdW functional to be used." Alberto is certain about using
PBE pseudos. One can even download them from the SIESTA website.

I just do not understand the meaning of "optionally changing the exchange
part by that of the vdW functional to be used". Does it mean this?

%block XC.hybrid
2
GGArevPBE   1   0
VDW   DRSLL0   1
%endblock XC.hybrid

Or this?

XC.Functional VDW
XC.authors  DRSLL

Bests,



On Tue, Aug 9, 2016 at 5:52 PM, I. Camps  wrote:

> Seyed,
>
> I think that you just have to generate the vdW pseudo directly using ATOM.
> Only that.
>
> Following the manual (ATOM 4.0.2 manual, page 13), you have the following
> flavors of vdW pseudos:
>
> Van der Waals (VDW) density functionals, implemented as Rom´an-P´erez and
> Soler,
> PRL 103, 096102 (2009):
> ∗ vw or vf: DRSLL (Dion et al, PRL 92, 246401 (2004))
> ∗ vl: LMKLL (Lee et al, PRB 82, 081101 (2010))
> ∗ vk: KBM (Klimes, Bowler, and Michaelides, JPCM 22, 022201 (2009))
> ∗ vc: C09 (Cooper, PRB 81, 161104 (2010))
> ∗ vb: BH (Berland and Hyldgaard, PRB 89, 035412 (2014))
> ∗ vv: VV (Vydrov and VanVoorhis, JCP 133, 244103 (2010))
>
> []'s,
>
> Camps
>
> On Tue, Aug 9, 2016 at 9:33 AM, Seyed Mohammad Tabatabaei <
> smt...@gmail.com> wrote:
>
>> Dear all,
>>
>> As I have understood, the DRSLL method for including the vdW interactions
>> takes its correlation from the revPBE but the exchange part is innovated by
>> the authors in the original DRSLL paper to include van der Waals
>> interactions. Now, should I use PBE pseudos or should I use revPBE pseudos
>> in my vdW calculations?
>>
>> Bests,
>>
>
>

Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[I. Camps]

Seyed,

I think that you just have to generate the vdW pseudo directly using ATOM.
Only that.

Following the manual (ATOM 4.0.2 manual, page 13), you have the following
flavors of vdW pseudos:

Van der Waals (VDW) density functionals, implemented as Rom´an-P´erez and
Soler,
PRL 103, 096102 (2009):
∗ vw or vf: DRSLL (Dion et al, PRL 92, 246401 (2004))
∗ vl: LMKLL (Lee et al, PRB 82, 081101 (2010))
∗ vk: KBM (Klimes, Bowler, and Michaelides, JPCM 22, 022201 (2009))
∗ vc: C09 (Cooper, PRB 81, 161104 (2010))
∗ vb: BH (Berland and Hyldgaard, PRB 89, 035412 (2014))
∗ vv: VV (Vydrov and VanVoorhis, JCP 133, 244103 (2010))

[]'s,

Camps

On Tue, Aug 9, 2016 at 9:33 AM, Seyed Mohammad Tabatabaei 
wrote:

> Dear all,
>
> As I have understood, the DRSLL method for including the vdW interactions
> takes its correlation from the revPBE but the exchange part is innovated by
> the authors in the original DRSLL paper to include van der Waals
> interactions. Now, should I use PBE pseudos or should I use revPBE pseudos
> in my vdW calculations?
>
> Bests,
>

Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[Seyed Mohammad Tabatabaei]

Dear all,

As I have understood, the DRSLL method for including the vdW interactions
takes its correlation from the revPBE but the exchange part is innovated by
the authors in the original DRSLL paper to include van der Waals
interactions. Now, should I use PBE pseudos or should I use revPBE pseudos
in my vdW calculations?

Bests,

Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[Seyed Mohammad Tabatabaei]

Unfortunately, I can not find any connection between my question and the answer.

On 8/5/16, Peter Koval  wrote:
> In case of silver atom, the pseudos provided by Rivero etal give a
> screwed up TDDFT spectra (without plasmonic peak, which is easy to
> reproduce with PPs provided by icmab
> http://departments.icmab.es/leem/siesta/Databases/Pseudopotentials/periodictable-intro.html)
>
> http://stacks.iop.org/0953-8984/28/i=21/a=214001
>
> Peter
>
>
> On Wed, Feb 17, 2016 at 1:00 PM, ticu Cubot  wrote:
>> Thank you very much for your reactions. Alberto's mail (indirectly)
>> implies
>> that GGA-PBE pseudos should be "reasonable". Along this line, can I
>> (without
>> experience in generating own pseudos, as Camps kindly suggested) conclude
>> that and use PBE pseudos from ABINIT or the SI of the recent study
>>
>> http://www.sciencedirect.com/science/article/pii/S0927025614007940
>>
>> Thanks again,
>>
>> ticu
>>
>> On Wed, Feb 17, 2016 at 12:36 PM, Alberto Garcia 
>> wrote:
>>>
>>> Hi,
>>>
>>> There is a subtle point concerning the use of the pseudopotential
>>> approximation with van der Waals functionals. In short, since the vdW xc
>>> term
>>> is non-local, the influence of the core can extend beyond the nominal
>>> "pseudopotential cutoff", leading to pseudos that can be pathological
>>> (for
>>> example, by converging to the coulomb tail too far out).
>>>
>>> For this reason, pseudopotentials generated with van der Waals
>>> functionals
>>> are not recommended. Instead, we recommend to generate the
>>> pseudopotentials
>>> with a good GGA functional like PBE, optionally changing the exchange
>>> part
>>> by that of the vdW functional to be used.
>>>
>>> This note will be added to the Siesta documentation as soon as possible.
>>>
>>>  Best regards,
>>>
>>>   Alberto
>>>
>>>
>>> On 17 Feb 2016, at 00:56, I. Camps  wrote:
>>>
>>> > Hello Ticu,
>>> >
>>> > You have to generate your own vdW-DFT pseudos.
>>> >
>>> > What I did:
>>> > - Download any INP (LDA or GGA) file from the SIESTA pseudos database
>>> > for your atoms,
>>> > - Change the head of the INP file and put the corresponding code for
>>> > your desired flavor of vdW-DFT functional (the codes for each
>>> > functional
>>> > type and the place in the INP file you can find in the ATOM manual),
>>> > - Generate the pseudo using the ATOM program (comes with SIESTA and
>>> > should be compiled separately with the same arch.file),
>>> > - Test the generated pseudo with the scripts that come with SIESTA.
>>> >
>>> >
>>> > []'s,
>>> >
>>> > Camps
>>> >
>>> > On Tue, Feb 16, 2016 at 9:10 PM, ticu Cubot 
>>> > wrote:
>>> > Hi Everybody!
>>> >
>>> > Because the manual of newly released 4.0b-485 does not address this
>>> > point, I would like to ask you: are the ABINIT pseudopotentials
>>> > suitable for
>>> > vdW-DFT calculations and, if so, which flavour (_lda, _gga)?
>>> >
>>> > Many thanks,
>>> > ticu
>>> >
>>>
>>
>

Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[Peter Koval]

In case of silver atom, the pseudos provided by Rivero etal give a
screwed up TDDFT spectra (without plasmonic peak, which is easy to
reproduce with PPs provided by icmab
http://departments.icmab.es/leem/siesta/Databases/Pseudopotentials/periodictable-intro.html)

http://stacks.iop.org/0953-8984/28/i=21/a=214001

Peter


On Wed, Feb 17, 2016 at 1:00 PM, ticu Cubot  wrote:
> Thank you very much for your reactions. Alberto's mail (indirectly) implies
> that GGA-PBE pseudos should be "reasonable". Along this line, can I (without
> experience in generating own pseudos, as Camps kindly suggested) conclude
> that and use PBE pseudos from ABINIT or the SI of the recent study
>
> http://www.sciencedirect.com/science/article/pii/S0927025614007940
>
> Thanks again,
>
> ticu
>
> On Wed, Feb 17, 2016 at 12:36 PM, Alberto Garcia  wrote:
>>
>> Hi,
>>
>> There is a subtle point concerning the use of the pseudopotential
>> approximation with van der Waals functionals. In short, since the vdW xc
>> term
>> is non-local, the influence of the core can extend beyond the nominal
>> "pseudopotential cutoff", leading to pseudos that can be pathological (for
>> example, by converging to the coulomb tail too far out).
>>
>> For this reason, pseudopotentials generated with van der Waals functionals
>> are not recommended. Instead, we recommend to generate the pseudopotentials
>> with a good GGA functional like PBE, optionally changing the exchange part
>> by that of the vdW functional to be used.
>>
>> This note will be added to the Siesta documentation as soon as possible.
>>
>>  Best regards,
>>
>>   Alberto
>>
>>
>> On 17 Feb 2016, at 00:56, I. Camps  wrote:
>>
>> > Hello Ticu,
>> >
>> > You have to generate your own vdW-DFT pseudos.
>> >
>> > What I did:
>> > - Download any INP (LDA or GGA) file from the SIESTA pseudos database
>> > for your atoms,
>> > - Change the head of the INP file and put the corresponding code for
>> > your desired flavor of vdW-DFT functional (the codes for each functional
>> > type and the place in the INP file you can find in the ATOM manual),
>> > - Generate the pseudo using the ATOM program (comes with SIESTA and
>> > should be compiled separately with the same arch.file),
>> > - Test the generated pseudo with the scripts that come with SIESTA.
>> >
>> >
>> > []'s,
>> >
>> > Camps
>> >
>> > On Tue, Feb 16, 2016 at 9:10 PM, ticu Cubot  wrote:
>> > Hi Everybody!
>> >
>> > Because the manual of newly released 4.0b-485 does not address this
>> > point, I would like to ask you: are the ABINIT pseudopotentials suitable 
>> > for
>> > vdW-DFT calculations and, if so, which flavour (_lda, _gga)?
>> >
>> > Many thanks,
>> > ticu
>> >
>>
>

Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[Seyed Mohammad Tabatabaei]

Dear Alberto Garcia,

I would be really grateful if you clarify a little more about the
following for me:

"Instead, we recommend to generate the pseudopotentials with a good
GGA functional like PBE, optionally changing the exchange part by that
of the vdW functional to be used."

Given the fact that .inp files are used with ATOM to generate pseudos,
do you mean that I have to change the .inp files of my previous
GGA-PBE pseudos from "pb" to "vw" (Not Changing Anything Else) and
generate my vdW pseudos? Or simply use pseudos generated with the "pb"
option in the .inp file (GGA-PBE pseudos) and set the following lines
in the main .fdf file instead?

XC.Functional VDW
XC.authors  DRSLL

If I use the latter strategy, I think the following warning in the
output file is always inevitable:

xc_check: Exchange-correlation functional:
xc_check: VDW Dion-Rydberg-Schroeder-Langreth-Lundqvist
xc_check: WARNING: Pseudopotential generated with GGA PBE functional

Please guide me on this issue. Should I ignore this warning?

Bests,
Mohammad,

Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[ticu Cubot]

Thank you very much for your reactions. Alberto's mail (indirectly) implies
that GGA-PBE pseudos should be "reasonable". Along this line, can I
(without experience in generating own pseudos, as Camps kindly suggested)
conclude that and use PBE pseudos from ABINIT or the SI of the recent study

http://www.sciencedirect.com/science/article/pii/S0927025614007940

Thanks again,

ticu

On Wed, Feb 17, 2016 at 12:36 PM, Alberto Garcia  wrote:

> Hi,
>
> There is a subtle point concerning the use of the pseudopotential
> approximation with van der Waals functionals. In short, since the vdW xc
> term
> is non-local, the influence of the core can extend beyond the nominal
> "pseudopotential cutoff", leading to pseudos that can be pathological (for
> example, by converging to the coulomb tail too far out).
>
> For this reason, pseudopotentials generated with van der Waals functionals
> are not recommended. Instead, we recommend to generate the pseudopotentials
> with a good GGA functional like PBE, optionally changing the exchange part
> by that of the vdW functional to be used.
>
> This note will be added to the Siesta documentation as soon as possible.
>
>  Best regards,
>
>   Alberto
>
>
> On 17 Feb 2016, at 00:56, I. Camps  wrote:
>
> > Hello Ticu,
> >
> > You have to generate your own vdW-DFT pseudos.
> >
> > What I did:
> > - Download any INP (LDA or GGA) file from the SIESTA pseudos database
> for your atoms,
> > - Change the head of the INP file and put the corresponding code for
> your desired flavor of vdW-DFT functional (the codes for each functional
> type and the place in the INP file you can find in the ATOM manual),
> > - Generate the pseudo using the ATOM program (comes with SIESTA and
> should be compiled separately with the same arch.file),
> > - Test the generated pseudo with the scripts that come with SIESTA.
> >
> >
> > []'s,
> >
> > Camps
> >
> > On Tue, Feb 16, 2016 at 9:10 PM, ticu Cubot  wrote:
> > Hi Everybody!
> >
> > Because the manual of newly released 4.0b-485 does not address this
> point, I would like to ask you: are the ABINIT pseudopotentials suitable
> for vdW-DFT calculations and, if so, which flavour (_lda, _gga)?
> >
> > Many thanks,
> > ticu
> >
>
>

Re: [SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[I. Camps]

Dear Alberto,

Thank you very much for your clarifications.

How can I change the exchange part by that of the vdW functional?


[]'s,

Camps

On Wed, Feb 17, 2016 at 9:36 AM, Alberto Garcia  wrote:

> Hi,
>
> There is a subtle point concerning the use of the pseudopotential
> approximation with van der Waals functionals. In short, since the vdW xc
> term
> is non-local, the influence of the core can extend beyond the nominal
> "pseudopotential cutoff", leading to pseudos that can be pathological (for
> example, by converging to the coulomb tail too far out).
>
> For this reason, pseudopotentials generated with van der Waals functionals
> are not recommended. Instead, we recommend to generate the pseudopotentials
> with a good GGA functional like PBE, optionally changing the exchange part
> by that of the vdW functional to be used.
>
> This note will be added to the Siesta documentation as soon as possible.
>
>  Best regards,
>
>   Alberto
>
>
> On 17 Feb 2016, at 00:56, I. Camps  wrote:
>
> > Hello Ticu,
> >
> > You have to generate your own vdW-DFT pseudos.
> >
> > What I did:
> > - Download any INP (LDA or GGA) file from the SIESTA pseudos database
> for your atoms,
> > - Change the head of the INP file and put the corresponding code for
> your desired flavor of vdW-DFT functional (the codes for each functional
> type and the place in the INP file you can find in the ATOM manual),
> > - Generate the pseudo using the ATOM program (comes with SIESTA and
> should be compiled separately with the same arch.file),
> > - Test the generated pseudo with the scripts that come with SIESTA.
> >
> >
> > []'s,
> >
> > Camps
> >
> > On Tue, Feb 16, 2016 at 9:10 PM, ticu Cubot  wrote:
> > Hi Everybody!
> >
> > Because the manual of newly released 4.0b-485 does not address this
> point, I would like to ask you: are the ABINIT pseudopotentials suitable
> for vdW-DFT calculations and, if so, which flavour (_lda, _gga)?
> >
> > Many thanks,
> > ticu
> >
>
>

[SIESTA-L] A note of warning regarding pseudopotentials for vdW-DFT calculations

[Alberto Garcia]

Hi,

There is a subtle point concerning the use of the pseudopotential approximation 
with van der Waals functionals. In short, since the vdW xc term
is non-local, the influence of the core can extend beyond the nominal 
"pseudopotential cutoff", leading to pseudos that can be pathological (for 
example, by converging to the coulomb tail too far out). 

For this reason, pseudopotentials generated with van der Waals functionals are 
not recommended. Instead, we recommend to generate the pseudopotentials with a 
good GGA functional like PBE, optionally changing the exchange part by that of 
the vdW functional to be used.

This note will be added to the Siesta documentation as soon as possible.

 Best regards,

  Alberto


On 17 Feb 2016, at 00:56, I. Camps  wrote:

> Hello Ticu,
> 
> You have to generate your own vdW-DFT pseudos.
> 
> What I did:
> - Download any INP (LDA or GGA) file from the SIESTA pseudos database for 
> your atoms,
> - Change the head of the INP file and put the corresponding code for your 
> desired flavor of vdW-DFT functional (the codes for each functional type and 
> the place in the INP file you can find in the ATOM manual),
> - Generate the pseudo using the ATOM program (comes with SIESTA and should be 
> compiled separately with the same arch.file),
> - Test the generated pseudo with the scripts that come with SIESTA.
> 
> 
> []'s,
> 
> Camps
> 
> On Tue, Feb 16, 2016 at 9:10 PM, ticu Cubot  wrote:
> Hi Everybody!
> 
> Because the manual of newly released 4.0b-485 does not address this point, I 
> would like to ask you: are the ABINIT pseudopotentials suitable for vdW-DFT 
> calculations and, if so, which flavour (_lda, _gga)? 
> 
> Many thanks,
> ticu
>