Is there any basis set updating during Car–Parrinello molecular dynamics?

[C C]

Hi,

 I have a very naive question. According to
https://www.cp2k.org/basis_sets
 CP2K adopted atomic centered Gaussian.

 From what I understood, in CPMD calculation, the potential energy surface is calculated on the fly (not prior constructed). During the MD simulation, nuclei changed their positions and overlap integrals will change. Will CP2K update its basis, i.e., adjust the center of basis function? Is there any near dependence in the calculation?

Thank you very much!

[C C]

> near dependence

linear dependence.

I am very sorry for my typo.

[Thomas Kühne]

Dear CC?, 

yes the basis functions are atom centered and hence move with the atoms causing 

that the overlap integrals needs to be recomputed whenever the positions are updated 

(e.g. geometry optimization, molecular dynamics, etc.). By default in CP2K ab-initio 

MD simulations are conducted by means of the Born-Oppenheimer scheme (the 

original CPMD method is not implemented), i.e. in every time-step a conventional 

electronic structure calculation is conducted. 

The de facto standard in CP2K are so-called „molecularly optimized“ basis set (aka 

MOLOPT basis), whose Gaussian exponents and contraction coefficients are optimized 

based on molecular systems using an objective function that is the sum of the total 

energy and the logarithm of the condition number of the overlap matrix. In this way, 

contrary to typical augmented basis sets, the overlap matrix is generally well conditioned, 

so that there are NO near linear dependencies in the basis, even for periodic systems!

Greetings, 

Thomas Kühne

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==============================

Thomas D. Kühne

Dynamics of Condensed Matter

Chair of Theoretical Chemistry

University of Paderborn

Warburger Str. 100

D-33098 Paderborn

Germany

tdku...@mail.upb.de

+49/(0)5251/60-5726

[C C]

Dear Professor Kühne,

  Thank you so much for your answer. I appreciate your help!

Best regards

[C C]

Dear Professor Kühne,

  Thank you once again for your kind and prompt reply. May I know some references for the basis set positions updating in MD used CP2K? I searched the docs of CP2K, but did not find any literature about this point (overlap integrals need to recomputed,  MOLOPT, etc).

  Thank you very much

在2020年11月26日星期四 UTC-5 上午2:51:12<tkuehne> 写道：