[Pw_forum] Environ-0.2 support Born-Oppenheimer MD ?

[Yang, Chi-Ta]

Dear Dr. Oliviero Andreussi,

Thanks a lot for your kind reply. It has cleared my questions.

Best,
Chi-Ta
University of Iowa
Postdoc
________________________________
From: pw_forum-bounces at pwscf.org <pw_forum-bounces at pwscf.org> on behalf of Oliviero Andreussi <oliviero.andreussi at usi.ch>
Sent: Tuesday, January 26, 2016 3:28 AM
To: PWSCF Forum
Subject: Re: [Pw_forum] Environ-0.2 support Born-Oppenheimer MD ?

Dear Chi-Ta,

In the pw.x code the MD engine is indeed Born-Oppenheimer (BO). In the cp.x code you also have Car-Parrinello and damped dynamics available. BO in pw.x was supported from the very first version of Environ-0.1 and from QE-5.1.X. Starting from the new releases of QE (5.3.0) and Environ (0.2), the effects of Environ can be used also with the cp.x code and with similar results. More info on what is supported and what is not can be found on the project/releases webpage http://www.quantum-environment.org/releases.html
[http://nebula.wsimg.com/a7ae43af29a30f7be916064b1327310d?AccessKeyId=ECF106C2B7F0B5C40F7B&disposition=0&alloworigin=1]<http://www.quantum-environment.org/releases.html>

Releases - Environ<http://www.quantum-environment.org/releases.html>
www.quantum-environment.org
Environ-0.1 is the first official release of Environ. It is interfaced with . the Quantum-ESPRESSO package and compatible with. versions QE-5.1, QE-5.1.1, and QE-5.1.2.




Please note the following points:
- the implemented environment embedding schemes are not (yet) dynamic, in the sense that, at any given time, they are computed on the given charge density of the QM system, with no retardation/memory/history effects. Thus, the dynamics performed with the continuum dielectric of Environ will not have its true meaning, but will provide a sort of more statistically averaged dynamics, in which at every step the solvent is fully equilibrated with the solute. Whether this suits your applications is hard to tell, but for sure it may provide some useful insights (and won't cost too much, compared to an explicit solvent simulation).
- the overhead of the Environ calculation with the two codes (pw.x and cp.x) is not the same, it is significantly smaller for the BO MD in the PW code: the cost of computing the embedding potential is the same in the two codes, but the cost of each electronic step is significantly different (much smaller in cp.x).

Please let me know if the above answers are not clear enough or if you have more doubts.

Best,

Oliviero Andreussi

P.S. Please remind to sign with your affiliation, when asking questions to this forum.



On 01/25/2016 04:08 PM, Yang, Chi-Ta wrote:

Dear All,


Sorry to ask this question. First, I would like to make sure that is MD in PWscf (PW) Born-Oppenheimer MD ?  Does Environ-0.2 support this MD?


Thanks a lot,

Chi-Ta




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--
Senior Postdoctoral Researcher
École Polytechnique Fédérale de Lausanne (EPFL) and
Università della Svizzera Italiana (USI) of Lugano
USI Campus, Via G. Buffi 17, 6904 Lugano, Switzerland
Emails: oliviero.andreussi @ epfl.ch -or- usi.ch
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