[DFTB-Plus-User] Energy problem about H2 and H2O

[Bálint Aradi]

Dear Lu,

>  I have using DFTB+ 1.0.1, and I have some doubts about the cluster energy in the result of autotest of H2O and H2. In the autotest of spin test, the total energy of H2 is -14.726823 eV, and the total energy of H2O is -101.594405 eV. My question is why the difference of total energy is so large (about 90 eV) for H2 and H2O, for they just have an O atom differnce?  Thanks for your attention, and hope to hear from you.  

 First of all, please do not use the autotest examples to draw any
conclusion about real calculations. Those are artifically created
examples, to test various features of the code. The geometries,
tolerances etc. in them can be completely unphysical, as their purpose
is to test the validity of certain features, and not to serve as example
input for the given test case.

  Concerning your concrete question. The energy of the single O atom is
exactly in the range you are missing.

  Best regards

    Bálint


-- 
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/en/~b_aradi


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