[CPMD-list] EHAM not conserved in NVE MD

[Axel Kohlmeyer]

On Wed, 21 Mar 2007, liu liuxiandong wrote:

LL> Dear all,
LL> 
LL> I performed a NVE CPMD on a system of ions-water. The derived EHAM firstly
LL> increases in the first 30 steps and then keeps conserved. I am not sure
LL> whether this behavior is normal.

yes it is, when you start from an optmized wavefunction 
with initial velocities on the ions (=atoms) and no matching
velocities on the electrons. this way the ions move, but the
wavefunction does not yet follow. if EHAM keeps conserved for
several thousand steps, you're fine. of course, this kind of
starting a CP-dynamics only works on systems with a large
band gap...

cheers,
   axel.

LL> 
LL> 
LL> Thanks for any suggestions.
LL> 

-- 
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Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
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