Dear all,
1)
I read from G. Kresse, J. Furthmuller/ Computational Materials Science 6
(1996) 15-50 at page 22 the following sentence: For the MP-method the
entropy term is a simple error estimateon for the difference between the
free energy F and the 'physically ' correct energy Es=0. s can be increased
until this error estimation gets larger than an allowed threshold (usually 1
meV).
My question is what exact value should I use for said "free energy" and "the
'physically ' correct energy Es=0"?
For example, in my output file
siesta: Program's energy decomposition (eV):
siesta: Eions = 1297.478215
siesta: Ena = 34.334398
siesta: Ekin = 1410.311338
siesta: Enl = -914.232279
siesta: DEna = -9.880177
siesta: DUscf = 0.976833
siesta: DUext = 0.000000
siesta: Exc = -765.088252
siesta: eta*DQ = 0.000000
siesta: Emadel = 0.000000
siesta: Ekinion = 0.000000
siesta: Eharris = -1541.056339
siesta: Etot = -1541.056355 # I think this is said the
'physically ' correct energy Es=0.
siesta: FreeEng = -1541.060715 # I think this is said Free
Energy.
siesta: Final energy (eV):
siesta: Kinetic = 1410.311338
siesta: Hartree = 155.823894
siesta: Ext. field = 0.000000
siesta: Exch.-corr. = -765.088252
siesta: Ion-electron = -1511.820672
siesta: Ion-ion = -830.282663
siesta: Ekinion = 0.000000
siesta: Total = -1541.056355 # I think this is said the
'physically ' correct energy Es=0.
I guess they are FreeEng = -1541.060715 and siesta: Total =
-1541.056355 or siesta: Total = -1541.056355, respectively.
Am I right? Can anybody tell me?
2)
I learned from Eur. Phys. J. B 40, 371-377(2004) that: Hamiltonian matrix
elements are partly computed on a real space grid, whose fineness Δx is
controlled by a grid cutoff, Ec=(p/Δx)2/2.
Does it mean that the charge density is represented on a regular real space
grid ofΔx? If not, where can I find the regular real space grid that
represents the charge density?
And what are the units ofΔx and Ec in that formula?
I will be grateful if anyone can help. Thanks in advance.
Best wishes!
Leila
