[DFTB-Plus-User] band structure by dftb+
刘雷
luminescence at ciomp.ac.cn
Tue Dec 4 03:34:34 CET 2012
Thank you very much for your explaination .The valence band calculated by dftb+ is in agreement with LDA while the conduction band is not,which verifies what you said.
However,what about diamond(C without d electron) ? It's bandstructure by dftb+ shows the same phenomenon as Si.
What's more,by using the DFTB+ in Material Studio,I got the correct bandstructrue of Si.
> -----原始邮件-----
> 发件人: dftb-plus-user-request at dftb-plus.info
> 发送时间: 2012年12月1日 星期六
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> 主题: DFTB-Plus-User Digest, Vol 59, Issue 1
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> Today's Topics:
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> 1. Dispersion model (SlaterKirkwood) (??)
> 2. Re: Dispersion model (SlaterKirkwood) (Benjamin Hourahine)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 1 Dec 2012 09:28:23 +0800 (CST)
> From: ?? <201031220001 at mail.bnu.edu.cn>
> To: dftb-plus-user at dftb-plus.info
> Subject: [DFTB-Plus-User] Dispersion model (SlaterKirkwood)
> Message-ID: <1418130.1733711354325303207.JavaMail.coremail at mail>
> Content-Type: text/plain; charset="gbk"
>
> Dear all,
>
> I want to calculate the dynamics process of the Muti-walled carbon nanotubes.
> So, the dispersion block is used to empirically correct the DFTB interactions for van der Waals interactions.
>
> The SlaterKirkwood dispersion model is implemented in my calculation, but i do not know whether the code is right,
> especially the CovalentRadius of the carbon.
> Below is my input file.
>
> Besides, in the user manual (page 34) of version 1.2 (DFTB+), it says that if atoms are able to move during your
> calculation (geometry relaxation or molecular dynamics) you should always check whether the coordination of your
> atoms has changed during the run. what does it mean?
>
> Geometry = GenFormat {
> <<< "geom.gen"
> }
> Driver = VelocityVerlet {
> MovedAtoms = 1:-1
> Steps = 10000
> KeepStationary = Yes
> TimeStep [fs] = 0.1
> OutputPrefix = "geom.out"
> Thermostat = None {}
> Velocities [AA/ps] = {
> <<< "velocity.txt"
> }
> ConvergentForcesOnly = Yes
> }
> Hamiltonian = DFTB {
> SCC = Yes
> SCCTolerance = 1.0e-5
> MaxSCCIterations = 10000
> OrbitalResolvedSCC = Yes
> Mixer = Broyden {
> MixingParameter = 0.2
> CachedIterations = -1
> InverseJacobiWeight = 1.000000000000000E-002
> MinimalWeight = 1.00000000000000
> MaximalWeight = 100000.000000000
> WeightFactor = 1.000000000000000E-002
> }
> MaxAngularMomentum = {
> C = "p"
> }
> SpinPolarisation = {}
> Eigensolver = RelativelyRobust{}
> Filling = Fermi {
> Temperature [Kelvin] = 1000.0
> }
> SlaterKosterFiles = {
> C-C = "C-C.skf"
> }
> KPointsAndWeights = {
> 0.0 0.0 0.0 1.0
> }
> OldSKInterpolation = No
> OldRepulsiveSum = No
> ReadInitialCharges = No
> Dispersion = SlaterKirkwood{
> PolarRadiusCharge =HybridDependentPol{
> C={
> CovalentRadius[Angstrom]=0.8
> HybridPolarisations [Angstrom^3, Angstrom,]={
> 1.382 1.382 1.382 1.064 1.064 1.064 3.8 3.8 3.8 3.8 3.8 3.8 2.5
> }
> }
> }
> }
> }
> Options = {
> WriteDetailedOut = Yes
> WriteBandOut = Yes
> }
> ParserOptions = {
> ParserVersion = 4
> StopAfterParsing = Yes
> }
>
> Thank you
> chao
>
>
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> ------------------------------
>
> Message: 2
> Date: Sat, 1 Dec 2012 08:27:24 +0000
> From: Benjamin Hourahine <benjamin.hourahine at strath.ac.uk>
> To: User list for DFTB+ related questions
> <dftb-plus-user at dftb-plus.info>
> Subject: Re: [DFTB-Plus-User] Dispersion model (SlaterKirkwood)
> Message-ID:
> <E4E5276EC6FFF04D8A733507AC9164A9016D417EC95A at E2K7-MS2.ds.strath.ac.uk>
>
> Content-Type: text/plain; charset="gb2312"
>
> Dear Chao,
>
> UFF dispersion is much easier to use, you might want to try it instead. The covalent radius
> in the Slater-Kirkwood model depends on the hybridization state of the atoms, so
> sp2 carbon has a different value from sp3. Your nanotube structures probably remain
> sp2 during the calculation,so use the appropriate values, but check for re-hybridization during
> the calculation.
>
> Regards
>
> Ben
>
> ________________________________________
> From: dftb-plus-user-bounces at dftb-plus.info [dftb-plus-user-bounces at dftb-plus.info] On Behalf Of ?? [201031220001 at mail.bnu.edu.cn]
> Sent: 01 December 2012 01:28
> To: dftb-plus-user at dftb-plus.info
> Subject: [DFTB-Plus-User] Dispersion model (SlaterKirkwood)
>
> Dear all,
>
> I want to calculate the dynamics process of the Muti-walled carbon nanotubes.
> So, the dispersion block is used to empirically correct the DFTB interactions for van der Waals interactions.
>
> The SlaterKirkwood dispersion model is implemented in my calculation, but i do not know whether the code is right,
> especially the CovalentRadius of the carbon.
> Below is my input file.
>
> Besides, in the user manual (page 34) of version 1.2 (DFTB+), it says that if atoms are able to move during your
> calculation (geometry relaxation or molecular dynamics) you should always check whether the coordination of your
> atoms has changed during the run. what does it mean?
>
> Geometry = GenFormat {
> <<< "geom.gen"
> }
> Driver = VelocityVerlet {
> MovedAtoms = 1:-1
> Steps = 10000
> KeepStationary = Yes
> TimeStep [fs] = 0.1
> OutputPrefix = "geom.out"
> Thermostat = None {}
> Velocities [AA/ps] = {
> <<< "velocity.txt"
> }
> ConvergentForcesOnly = Yes
> }
> Hamiltonian = DFTB {
> SCC = Yes
> SCCTolerance = 1.0e-5
> MaxSCCIterations = 10000
> OrbitalResolvedSCC = Yes
> Mixer = Broyden {
> MixingParameter = 0.2
> CachedIterations = -1
> InverseJacobiWeight = 1.000000000000000E-002
> MinimalWeight = 1.00000000000000
> MaximalWeight = 100000.000000000
> WeightFactor = 1.000000000000000E-002
> }
> MaxAngularMomentum = {
> C = "p"
> }
> SpinPolarisation = {}
> Eigensolver = RelativelyRobust{}
> Filling = Fermi {
> Temperature [Kelvin] = 1000.0
> }
> SlaterKosterFiles = {
> C-C = "C-C.skf"
> }
> KPointsAndWeights = {
> 0.0 0.0 0.0 1.0
> }
> OldSKInterpolation = No
> OldRepulsiveSum = No
> ReadInitialCharges = No
> Dispersion = SlaterKirkwood{
> PolarRadiusCharge =HybridDependentPol{
> C={
> CovalentRadius[Angstrom]=0.8
> HybridPolarisations [Angstrom^3, Angstrom,]={
> 1.382 1.382 1.382 1.064 1.064 1.064 3.8 3.8 3.8 3.8 3.8 3.8 2.5
> }
> }
> }
> }
> }
> Options = {
> WriteDetailedOut = Yes
> WriteBandOut = Yes
> }
> ParserOptions = {
> ParserVersion = 4
> StopAfterParsing = Yes
> }
>
> Thank you
> chao
>
>
>
>
> ------------------------------
>
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> End of DFTB-Plus-User Digest, Vol 59, Issue 1
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