Murnaghan equation for lattice parameters???

[new_986]

Hi everybody...
I'm trying to determine lattice constant (a) for BN by calculating the total energy for different values of a using ABINIT, then chose the one which correspond the minimum value of energy, Is this convenient way to determine a ??
the second question, Is Murnaghan equation implemented in the Abinit??

Thanks...
with regards...

[jzwanzig]

Well, you can determine the lattice constants the way you say, but I think it is much easier and more robust to use the ionmov and optcell inputs. Is there a reason why you are doing it directly without making use of ionmov and optcell?

Secondly, the Murnahan eqn is not coded in abinit, what you would do is extract the total energies and unit cell volumes from a series of runs and paste them into a graphing program or script of your own to do the equation fit.

[new_986]

Well, you can determine the lattice constants the way you say, but I think it is much easier and more robust to use the ionmov and optcell inputs. Is there a reason why you are doing it directly without making use of ionmov and optcell?

Secondly, the Murnahan eqn is not coded in abinit, what you would do is extract the total energies and unit cell volumes from a series of runs and paste them into a graphing program or script of your own to do the equation fit.

To me, the way I'm using is easier than the way what is using ionmove, but the Murnahan eqn. gives bulk modules too.
the second suggestion is good.
thanks a lot with best regards