[DFTB-Plus-User] DFTB-Plus-User Digest, Vol 40, Issue 3

Ben Hourahine benjamin.hourahine at strath.ac.uk
Wed Apr 20 14:16:33 CEST 2011


I've tested your input with another geometry, the large value of
CouplingStrength is responsible. Reduce this to around 0.1  or less
(magnitude of temperature fluctuations).


bigcontinent wrote:
> Thank you for your advise, but the geometry structure of C60 has been
> relaxed. I also adjust the values of
> temperature and CouplingStrength, still failure. I noted a strange thing
> in output. I use NVT essamble, but the temperature is changed and then
> the calculation stops.
>  
> ********************************************************************************
> ** Geometry step: 1
> ********************************************************************************
>  
>   iSCC Total electronic   Diff electronic      SCC error    
>     1   -0.10745145E+03    0.00000000E+00    0.72870867E-04
>     2   -0.10745145E+03   -0.72495254E-09    0.28925391E-04
>     3   -0.10745145E+03   -0.96349595E-11    0.77919338E-05
>  
>  Total Energy:                    -103.2321664545 H
>  Total Mermin free energy:        -103.2321664545 H
>>> Charges saved for restart in charges.bin
>  MD Temperature::                    0.0015834076 H          500.0000 K
>  MD Kinetic Energy:                  0.1401315708 H
>  Total MD Energy:                 -103.0920348836 H
>  
> ********************************************************************************
> ** Geometry step: 2
> ********************************************************************************
>  
>   iSCC Total electronic   Diff electronic      SCC error    
>     1   -0.10745150E+03    0.00000000E+00    0.80740245E-04
>     2   -0.10745150E+03   -0.99765884E-09    0.32024853E-04
>     3   -0.10745150E+03    0.60921934E-10    0.10973196E-04
>     4   -0.10745150E+03   -0.26486191E-09    0.37197280E-05
>  
>  Total Energy:                    -103.2321660027 H
>  Total Mermin free energy:        -103.2321660027 H
>>> Charges saved for restart in charges.bin
>  MD Temperature::                    0.0015835835 H          500.0555 K
>  MD Kinetic Energy:                  0.1401471387 H
>  Total MD Energy:                 -103.0920188640 H
>  
> ********************************************************************************
> ** Geometry step: 3
> ********************************************************************************
>  
>   iSCC Total electronic   Diff electronic      SCC error    
>     1   -0.10745154E+03    0.00000000E+00    0.73174567E-04
>     2   -0.10745154E+03   -0.72488149E-09    0.28752079E-04
>     3   -0.10745154E+03   -0.28776981E-10    0.70217462E-05
>  
>  Total Energy:                    -103.2321652482 H
>  Total Mermin free energy:        -103.2321652482 H
>>> Charges saved for restart in charges.bin
>  MD Temperature::                    0.0015663372 H          494.6096 K
>  MD Kinetic Energy:                  0.1386208466 H
>  Total MD Energy:                 -103.0935444016 H
>  
> ********************************************************************************
> ** Geometry step: 4
> ********************************************************************************
>  
>   iSCC Total electronic   Diff electronic      SCC error    
>     1   -0.10745159E+03    0.00000000E+00    0.79588420E-04
>     2   -0.10745159E+03   -0.98479802E-09    0.32093166E-04
>     3   -0.10745159E+03    0.26147973E-11    0.10050975E-04
>     4   -0.10745159E+03   -0.16945023E-09    0.31384297E-05
>  
>  Total Energy:                    -103.2321641975 H
>  Total Mermin free energy:        -103.2321641975 H
>>> Charges saved for restart in charges.bin
>  MD Temperature::                    0.0032738759 H         1033.8070 K
>  MD Kinetic Energy:                  0.2897380198 H
>  Total MD Energy:                 -102.9424261777 H
>  
> ********************************************************************************
> ** Geometry step: 5
> ********************************************************************************
>  
>   iSCC Total electronic   Diff electronic      SCC error    
>     1   -0.10745167E+03    0.00000000E+00    0.10604285E-03
>     2   -0.10745167E+03   -0.15088517E-08    0.40885467E-04
>     3   -0.10745167E+03   -0.34347636E-10    0.10805028E-04
>     4   -0.10745167E+03   -0.12717294E-09    0.35450370E-05
>  
>  Total Energy:                    -103.2321621491 H
>  Total Mermin free energy:        -103.2321621491 H
>>> Charges saved for restart in charges.bin
>  MD Temperature::                             NaN H               NaN K
>  MD Kinetic Energy:                           NaN H
>  Total MD Energy:                             NaN H
>  
> ********************************************************************************
> ** Geometry step: 6
> ********************************************************************************
>  
>   iSCC Total electronic   Diff electronic      SCC error    
> ERROR!
> -> Failure in diagonalisation routine dsygvd, non-positive definite overlap! Minor      1 responsible.
>  
>  
> 2011-04-20
> ------------------------------------------------------------------------
> bigcontinent
> ------------------------------------------------------------------------
> *发件人:* dftb-plus-user-request
> *发送时间:* 2011-04-20  18:32:24
> *收件人:* dftb-plus-user
> *抄送:*
> *主题:* DFTB-Plus-User Digest, Vol 40, Issue 3
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> Today's Topics:
>    1. Failure on MD run (bigcontinent)
>    2. Re: Failure on MD run (Ben Hourahine)
> ----------------------------------------------------------------------
> Message: 1
> Date: Wed, 20 Apr 2011 11:55:29 +0800
> From: "bigcontinent" <bigcontinent at 163.com>
> Subject: [DFTB-Plus-User] Failure on MD run
> To: "dftb-plus-user" <dftb-plus-user at dftb-plus.info>
> Message-ID: <201104201155287032753 at 163.com>
> Content-Type: text/plain; charset="us-ascii"
> Hi, everyone
>      I would like to run an MD simulation of C60 using DFTB+, but I get the following message, 
> ********************************************************************************
> ** Geometry step: 3
> ********************************************************************************
>   iSCC Total electronic   Diff electronic      SCC error    
> ERROR!
> -> Failure in diagonalisation routine dsygvd, non-positive definite overlap! Minor      1 responsible.
>        My investigated sytem is C60 and temperature is set to 300K, using Berendsen  ensemble . 
> My INPUT
> Driver = VelocityVerlet{
>   Steps = 2500000                  # Number of MD steps to perform
>   TimeStep [Femtosecond] = 0.2      # Time step in femtoseconds
>   OutputPrefix = "last"
>   Thermostat =  Berendsen {  
>   Temperature [Kelvin] = 300.0
>  CouplingStrength = 500.0
> }
> }
> Hamiltonian = DFTB {
>   SCC = Yes
>   SCCTolerance = 1.0e-5
>   MaxSCCIterations = 1000
>   Mixer = Broyden {
>     MixingParameter = 0.2
>   }
>   SlaterKosterFiles = {
>     C-C = "C-C.skf"
>   }
> MaxAngularMomentum = {
>     C = "p"
>   }
>   Charge = 0.0
>   SpinPolarisation = {}
>   Filling = Fermi {
>     Temperature [Kelvin] = 300.0
>   }
> }
> Options = {}
> ParserOptions = {
>   ParserVersion = 3
> }
>         Please give me some advices. 
>         Thank you very much
> 2011-04-20 
> bigcontinent 
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> ------------------------------
> Message: 2
> Date: Wed, 20 Apr 2011 06:53:50 +0100
> From: Ben Hourahine <benjamin.hourahine at strath.ac.uk>
> Subject: Re: [DFTB-Plus-User] Failure on MD run
> To: User list for DFTB+ related questions
> <dftb-plus-user at dftb-plus.info>
> Message-ID: <4DAE74EE.2050006 at strath.ac.uk>
> Content-Type: text/plain; charset="iso-8859-1"
> Your initial geometry is probably the cause of the problem, did you 
> relax it first with conjugate
> gradient or similar? Also the thermostat coupling strength is very large 
> (temperature
> will be very strongly forced towards 300K).
> On 20/04/11 04:55, bigcontinent wrote:
>> Hi, everyone
>>      I would like to run an MD simulation of C60 using DFTB+, but I 
>> get the following message,
>> //
>> /**********************************************************************************/
>> /*** Geometry step: 3*/
>> /**********************************************************************************/
>> /** /
>> /*  iSCC Total electronic   Diff electronic      SCC error */
>> /*ERROR!*/
>> /*-> Failure in diagonalisation routine dsygvd, non-positive definite overlap! Minor      1 responsible.*/
>> //
>> //   My investigated sytem is C60 and temperature is set to 300K, 
>> using Berendsen  ensemble .
>> My INPUT
>> Driver = VelocityVerlet{
>>   Steps = 2500000                  # Number of MD steps to perform
>>   TimeStep [Femtosecond] = 0.2      # Time step in femtoseconds
>>   OutputPrefix = "last"
>>   Thermostat =  Berendsen {
>>   Temperature [Kelvin] = 300.0
>>  CouplingStrength = 500.0
>> }
>> }
>> Hamiltonian = DFTB {
>>   SCC = Yes
>>   SCCTolerance = 1.0e-5
>>   MaxSCCIterations = 1000
>>   Mixer = Broyden {
>>     MixingParameter = 0.2
>>   }
>>   SlaterKosterFiles = {
>>     C-C = "C-C.skf"
>>   }
>> MaxAngularMomentum = {
>>     C = "p"
>>   }
>>   Charge = 0.0
>>   SpinPolarisation = {}
>>   Filling = Fermi {
>>     Temperature [Kelvin] = 300.0
>>   }
>> }
>> Options = {}
>> ParserOptions = {
>>   ParserVersion = 3
>> }
>>         Please give me some advices.
>>         Thank you very much
>> 2011-04-20
>> ------------------------------------------------------------------------
>> bigcontinent
> -- 
>       Dr. B. Hourahine, SUPA, Department of Physics,
>     University of Strathclyde, John Anderson Building,
>            107 Rottenrow, Glasgow G4 0NG, UK.
>      +44 141 548 2325, benjamin.hourahine at strath.ac.uk
>     The University of Strathclyde is a charitable body,
> registered in Scotland, with registration number SC015263
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> *********************************************
> 

-- 
     Dr. B. Hourahine, SUPA, Department of Physics,
   University of Strathclyde, John Anderson Building,
          107 Rottenrow, Glasgow G4 0NG, UK.
    +44 141 548 2325, benjamin.hourahine at strath.ac.uk
   The University of Strathclyde is a charitable body,
registered in Scotland, with registration number SC015263



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