smearing in gamma point calculations
Posted: Thu Apr 11, 2013 1:04 pm
Hi all,
I'm modelling a series of molecular systems in a large box (20A) using gamma point sampling. What would the most appropriate smearing method to use be? So far I've been using Gaussian smearing
Some of the systems have several partially filled near degenerate bands at the fermi level. When calculating phonons (using IBRION=5), I'm getting a single negative frecuency (~200cm-1) in the systems that have density at the fermi level, which I think is coming from unequal occupancy of the orbitals. When I force equal occupancy of the degenerate orbitals, the structure becomes more symmetric.
Thanks in advance for any advice,
I'm modelling a series of molecular systems in a large box (20A) using gamma point sampling. What would the most appropriate smearing method to use be? So far I've been using Gaussian smearing
Some of the systems have several partially filled near degenerate bands at the fermi level. When calculating phonons (using IBRION=5), I'm getting a single negative frecuency (~200cm-1) in the systems that have density at the fermi level, which I think is coming from unequal occupancy of the orbitals. When I force equal occupancy of the degenerate orbitals, the structure becomes more symmetric.
Thanks in advance for any advice,