differences in ionic calculation

boy7478 · Post by **boy7478** » Tue Apr 17, 2007 9:42 am

Hi all,
recently i performed NEB and the result was the energy was different at the end of calculation.
i copy last 2 steps :
==========================
DAV: 26 -0.424675102022E+03 0.25165E-03 -0.42306E-04 492 0.138E-01 0.623E-02
DAV: 27 -0.424675046867E+03 0.55155E-04 -0.78678E-05 356 0.542E-02
1 F= -.84935009E+03 E0= -.84930514E+03 d E =-.849350E+03
damped: g(F)= NAN g(S)= 0.000E+00 dE (1.order)= -NAN
reached required accuracy - stopping structural energy minimisation
writing wavefunctions
===========================
why the energy in 1F is different with energy in step 26 or 27?
because in ordinary calculation the energy would be the same.

thank you!

Post by **graeme** » Tue Apr 17, 2007 3:29 pm

The energy that vasp reports in the 1F line is the sum of the energy of all images. In this case, it looks like you have 2 images so that the final energy is twice that in the loop.