[CP2K-user] [CP2K:14294] Is there any basis set updating during Car–Parrinello molecular dynamics?

C C wc0... at gmail.com
Thu Nov 26 22:26:25 UTC 2020


Dear Professor Kühne,

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

Best regards

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

> 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
>
> Am 26.11.2020 um 00:48 schrieb C C <w... at gmail.com>:
>
> 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! 
>
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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
> td... at mail.upb.de
> +49/(0)5251/60-5726 <+49%205251%20605726>
>
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