[DFTB-Plus-User] Energy Conservation for MD in dftb+

[gxaaas]

Hi Ben，
  Thanks for your reply. For my systems, Yes, it contains H atoms.  
  Considering the ensemble， I'm using ' Thermostat = None { InitialTemperature [Kelvin] = 300.0000000000  } 
  If take the time step with 0.1fs, the oscillation range decrease to about 1meV. 

 Best,



gxaaas

发件人： Ben Hourahine
发送时间： 2012-12-18 18:29
收件人： gxaaas; User list for DFTB+ related questions
主题： Re: [DFTB-Plus-User] Energy Conservation for MD in dftb+
Hello gxaaas,

your system probably contains H atoms bonded to something light, the time step needs to be fast enough to properly sample the 
vibrational dynamics. I'd first try a smaller time step (0.1fs). Just to check, you are using an NVE ensemble, so no thermostat or barostat?

Regards

Ben


On 18/12/12 08:08, gxaaas wrote:

Hi all, 
    When I test the MD in dftb+ for system of about 2000 atoms with 'SCCTolerance = 1.0E-005', 'TimeStep = 0.5 fs', the final total MD energy oscillate around 150meV.   Could someone give comments on this point, should the range be smaller for general MD simulation?
Thanks! 



gxaaas


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