[Pw_forum] 回复： Can the result of relax mode be recongnized as one representive of snapshots of molecular dynamics?

[Huiqun Zhou]

shaofeng,

I don't think you can generally think that way, they are different.  

In short, the process of relaxation (structure optimization) is mathematical, while
the process of MD is physical. Putting it in a clearer way, the movement of ions in
a system during relaxation is ruled by the algorithms you are using, whether Newton-like, 
or conjugate gradient, and the trajectory of the movement is meaningless. In MD, the
movement of atoms in a system is assumed to obey classical mechanics, and the evolving 
trajectory of the system is obtained by solving a system of ordinary differential 
equations. This trajectory can be used to calculate various physical properties of the
system.

In case you are considering crystal structure of the system at T=0 K, the result of 
relaxation, ONLY the structure, is indeed coincident to the average of last a few 
snapshots of a MD trajectory in equilibrium at T=0 K. That's why there is option of MD 
for structural optimization in other DFT code.   


Huiqun Zhou at Earth Sciences
Nanjing University, China


----- 原始邮件 -----
发件人: "Shaofeng Wang" <wangshaofeng at iae.ac.cn>
收件人: pw forum <pw_forum at pwscf.org>
已发送邮件: Wed, 17 Jun 2015 00:33:19 +0800 (CST)
主题: [Pw_forum] Can the result of relax mode be recongnized as one
	representive of snapshots of molecular dynamics?

Dear all,

Can the result of relax mode be recongnized as one representive of snapshots 
of molecular dynamics?

Regards,

Shaofeng



--------------------------------------
Shaofeng Wang, Ph.D
Environmental Molecular Science Group
Institute of Applied Ecology, Chinese Academy of Sciences
Shenyang, 110016, China
wangshaofeng at iae.ac.cn
www.iae.cas.cn 


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