Re: [SIESTA-L] [***Posible SPAM***]2

[sauluck]

barnali,
send a ps or pdf fileof the band structure & name of compound.
s.auluck

> Thank you sir for your kind response. My system is a metallic one where
> the
> Fermi energy sifted towards conduction band due to doping. For details
> here
> I am attaching the band structure. Do you think should I include drude
> term? Kindly guide me to chose relaxation time for my system.
>
> I am waiting for your suggestion.
>
> Thanks in advance.
>
> Sincerely
> Barnali
>
>
> On Wed, Feb 17, 2016 at 6:02 PM,  wrote:
>
>> barnali,
>> drude term is to included only when a band/bands cut the fermi
>> energy...for
>> metals,semimetals..if you have an energy gap then you have only
>> interband contributions..no drde term.
>> s.auluck
>>
>> > Respected SIESTA users (Marty Blaber)
>> >
>> > I am calculating the optical properties of  a graphene like  2D sheet
>> > using
>> > SIESTA 3.2. The band structure confirms its metallic nature and  the
>> > *.EPSIMG (was generated after optical calculation) shows  W_p is
>> non-zero,
>> > i.e.  W_p =0.0013.  As I know that the  drude term is to be included
>> for
>> > metal, now my queries are -
>> > For calculating optical properties  using optical.f should I  include
>> > drude term?
>> >  Is it necessary to include drude term for my system? If it is
>> necessary,
>> > then how can I choose relaxation time?  I will be grateful if anyone
>> > guide
>> > me to choose relaxation time for graphene like 2D sheet? I am waiting
>> for
>> > any response.
>> >
>> > Thanks in advance.
>> >
>> > Sincerely
>> > Barnali Bhattacharya
>> > Ph.D. Student,
>> >  Assam University, Silchar, India
>> >
>>
>>
>> --
>> Prof. Sushil Auluck  Phone:+91-512-6797092/6148
>> Department of Physics  +91-512-6798177(Home)
>> Indian Institute of Technology   Cell :+91-9305548667
>> Kanpur 208016 (UP)   Fax  :+91-512-6790914
>> IndiaE-mail:saul...@iitk.ac.in
>>  ...:saul...@gmail.com
>> http://www.iitk.ac.in/phy/People/phy_facvis.html
>> http://www.iitk.ac.in/phy/New01/profile_SA.html
>> http://www.iitk.ac.in/phy/index.php/people/faculty
>>
>> http://www.iitk.ac.in/phy/index.php/people/faculty/12-people/faculty/profile/88-sushil-auluck
>> ...
>> ~
>>
>


-- 
Prof. Sushil Auluck  Phone:+91-512-6797092/6148
Department of Physics  +91-512-6798177(Home)
Indian Institute of Technology   Cell :+91-9305548667
Kanpur 208016 (UP)   Fax  :+91-512-6790914
IndiaE-mail:saul...@iitk.ac.in
 ...:saul...@gmail.com
http://www.iitk.ac.in/phy/People/phy_facvis.html
http://www.iitk.ac.in/phy/New01/profile_SA.html
http://www.iitk.ac.in/phy/index.php/people/faculty
http://www.iitk.ac.in/phy/index.php/people/faculty/12-people/faculty/profile/88-sushil-auluck
...
~

Re: [SIESTA-L] [***Posible SPAM***]2

[Barnali Bhattacharya]

Thank you sir for your kind response. My system is a metallic one where the
Fermi energy sifted towards conduction band due to doping. For details here
I am attaching the band structure. Do you think should I include drude
term? Kindly guide me to chose relaxation time for my system.

I am waiting for your suggestion.

Thanks in advance.

Sincerely
Barnali


On Wed, Feb 17, 2016 at 6:02 PM,  wrote:

> barnali,
> drude term is to included only when a band/bands cut the fermi energy...for
> metals,semimetals..if you have an energy gap then you have only
> interband contributions..no drde term.
> s.auluck
>
> > Respected SIESTA users (Marty Blaber)
> >
> > I am calculating the optical properties of  a graphene like  2D sheet
> > using
> > SIESTA 3.2. The band structure confirms its metallic nature and  the
> > *.EPSIMG (was generated after optical calculation) shows  W_p is
> non-zero,
> > i.e.  W_p =0.0013.  As I know that the  drude term is to be included for
> > metal, now my queries are -
> > For calculating optical properties  using optical.f should I  include
> > drude term?
> >  Is it necessary to include drude term for my system? If it is necessary,
> > then how can I choose relaxation time?  I will be grateful if anyone
> > guide
> > me to choose relaxation time for graphene like 2D sheet? I am waiting for
> > any response.
> >
> > Thanks in advance.
> >
> > Sincerely
> > Barnali Bhattacharya
> > Ph.D. Student,
> >  Assam University, Silchar, India
> >
>
>
> --
> Prof. Sushil Auluck  Phone:+91-512-6797092/6148
> Department of Physics  +91-512-6798177(Home)
> Indian Institute of Technology   Cell :+91-9305548667
> Kanpur 208016 (UP)   Fax  :+91-512-6790914
> IndiaE-mail:saul...@iitk.ac.in
>  ...:saul...@gmail.com
> http://www.iitk.ac.in/phy/People/phy_facvis.html
> http://www.iitk.ac.in/phy/New01/profile_SA.html
> http://www.iitk.ac.in/phy/index.php/people/faculty
>
> http://www.iitk.ac.in/phy/index.php/people/faculty/12-people/faculty/profile/88-sushil-auluck
> ...
> ~
>


2N_CHAIN
Description: Binary data

Re: [SIESTA-L] [***Posible SPAM***]2

[sauluck]

barnali,
drude term is to included only when a band/bands cut the fermi energy...for
metals,semimetals..if you have an energy gap then you have only
interband contributions..no drde term.
s.auluck

> Respected SIESTA users (Marty Blaber)
>
> I am calculating the optical properties of  a graphene like  2D sheet
> using
> SIESTA 3.2. The band structure confirms its metallic nature and  the
> *.EPSIMG (was generated after optical calculation) shows  W_p is non-zero,
> i.e.  W_p =0.0013.  As I know that the  drude term is to be included for
> metal, now my queries are -
> For calculating optical properties  using optical.f should I  include
> drude term?
>  Is it necessary to include drude term for my system? If it is necessary,
> then how can I choose relaxation time?  I will be grateful if anyone
> guide
> me to choose relaxation time for graphene like 2D sheet? I am waiting for
> any response.
>
> Thanks in advance.
>
> Sincerely
> Barnali Bhattacharya
> Ph.D. Student,
>  Assam University, Silchar, India
>


-- 
Prof. Sushil Auluck  Phone:+91-512-6797092/6148
Department of Physics  +91-512-6798177(Home)
Indian Institute of Technology   Cell :+91-9305548667
Kanpur 208016 (UP)   Fax  :+91-512-6790914
IndiaE-mail:saul...@iitk.ac.in
 ...:saul...@gmail.com
http://www.iitk.ac.in/phy/People/phy_facvis.html
http://www.iitk.ac.in/phy/New01/profile_SA.html
http://www.iitk.ac.in/phy/index.php/people/faculty
http://www.iitk.ac.in/phy/index.php/people/faculty/12-people/faculty/profile/88-sushil-auluck
...
~

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
> 

[SIESTA-L] [***Posible SPAM***]2

[Barnali Bhattacharya]

Respected SIESTA users (Marty Blaber)

I am calculating the optical properties of  a graphene like  2D sheet using
SIESTA 3.2. The band structure confirms its metallic nature and  the
*.EPSIMG (was generated after optical calculation) shows  W_p is non-zero,
i.e.  W_p =0.0013.  As I know that the  drude term is to be included for
metal, now my queries are -
For calculating optical properties  using optical.f should I  include
drude term?
 Is it necessary to include drude term for my system? If it is necessary,
then how can I choose relaxation time?  I will be grateful if anyone  guide
me to choose relaxation time for graphene like 2D sheet? I am waiting for
any response.

Thanks in advance.

Sincerely
Barnali Bhattacharya
Ph.D. Student,
 Assam University, Silchar, India

Re: [SIESTA-L] Pseudopotentials for vdW-DFT

[I. Camps]

Mayuri Vaghela,

Please do not contaminate the thread with new/different questions!

Create your own thread.


[]'s,

Camps

On Wed, Feb 17, 2016 at 3:53 AM, Mayuri Vaghela 
wrote:

> Hi every body,
> i got below error when i run calculation.
> "Error in Cholesky factorisation in cdiag
> ERROR STOP from Node:0"
> please help me. i am attaching my input file with this mail.
>
>
> On Wed, Feb 17, 2016 at 5:26 AM, 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
>>>
>>
>>
>