I got the energy differences which are less than 10eV and I guess they are corrent . But can you please tell me what is the uncertainity in the energies that i get. This is the output that i got.
siesta: Final energy (eV): siesta: Kinetic = 148077.062865 siesta: Hartree = 1387018.221902 siesta: Ext. field = 0.000000 siesta: Exch.-corr. = -20554.562630 siesta: Ion-electron =-2900798.341991 siesta: Ion-ion = 1266423.882434 siesta: Ekinion = 0.000000 siesta: Total = -119833.737421 siesta: Atomic forces (eV/Ang): siesta: 1 2.254951 1.301912 0.921874 siesta: 2 -0.073621 1.977399 1.398322 . . . siesta: 126 0.032933 -2.375644 -1.678582 siesta: Tot 0.012066 0.008208 -0.123697 siesta: Stress tensor (static) (eV/Ang**3): siesta: 0.002093 0.000205 0.000146 siesta: 0.000205 0.001856 0.000084 siesta: 0.000146 0.000084 0.001860 On Thu, Jul 15, 2010 at 2:00 AM, tarang mungole <[email protected]>wrote: > Sorry for the way I asked the question.... > > Thanks for your reply....well I checked the geometry in Xcrysden and it > showed the correct picture(if I replicate the picture in all directions) . > Actually apart from this , I calculated the energies of the slabs extending > upto infinity in 2 directions and restricted in the z direction by giving a > big vacuum space in the unit cell(I guess this is the cluster you are > talking about). I used Ni infinite slabs, then i used Ni infinite slabs with > adatoms and calculated the enery differences and the differences were like > 10KeV! > Well in this case, I had put a big vacuum space in all the 3 directions > and it says that virtual memory is not enough > > InitMesh: MESH = 500 x 500 x 500 = 125000000 > InitMesh: Mesh cutoff (required, used) = 100.000 104.475 Ry > forrtl: severe (41): insufficient virtual memory > > > On Wed, Jul 14, 2010 at 1:10 PM, N H <[email protected]> wrote: > >> Did you checked the output geometry to see whether this is really the >> geometry you want or not? >> >> Another question: Do you like to calculate a Slab or a cluster? It seems >> that your calculation is set to a Cluster. >> >> It is also not clear which energy you would like to calculate. Remember >> that absolute total energies calculated with SIESTA ( or any other method ) >> have no meaning in itself - once the energy reference is arbitrary. You have >> to compare it with the energy of another well-defined system >> and establish energy differences. >> >> Just to give an idea, I calculate ZnO slabs with more or less 40 atoms ( >> including some molecules adsorbed ) and the total energies are something >> like -35KeV ... and it is normal. >> >> A last tip: The people here in this list use to be very friendly and >> helpful. So there is no need to urging someone to solve the problem you >> posted with "It's very urgent!!". Everybody here is open to help each other, >> but everybody here also have urgent stuff to do besides answering the SIESTA >> mail-L. If you want help, please ask it nicely. >> >> Best Regards >> >> >> NH >> >> >> >> >> On Wed, Jul 14, 2010 at 12:01 PM, Juan Beltran < >> [email protected]> wrote: >> >>> I find that your system do not have that many C atoms, how does the >>> energy compare with a pure Ni system?, still large?. Compare also the energy >>> you obtain for that big supercell with the pure FCC Ni system (1 atom may >>> do). The difference should be due to the presence of vacum along the three >>> directions and I guess it should be less that 100eV from the 50KeV you >>> obtain from the large system. >>> >>> Juan >>> >>> On 07/14/2010 12:45 AM, tarang mungole wrote: >>> >>>> I have made a slab with FCC configuration and I want to calculate the >>>> energy of the slab!! The slab contains 5 layers of Nickel atoms and a >>>> carbon >>>> atom on the top of it. I just want to calculate the energy of this >>>> system!!! >>>> ....I made a supercell having 5X5X5 lattice constants in each direction ( >>>> 5a >>>> 5a 5a 60 60 60) and then gave a BIG vaccum space so that the nearby >>>> Replicated supercells do not interact.(Is this a correct concept??????) . >>>> The problem is that the energies that i get are very large!!!! about >>>> -50KeV!! Can any body tell what is wrong in my fdf input file....it's very >>>> urgent!! >>>> >>>> ---------------------------------------------------FDF >>>> FILE---------------------------------------------------------------------------------------------------------------------------------------------- >>>> >>>> %block ChemicalSpeciesLabel >>>> 1 28 Ni >>>> 2 6 C >>>> %endblock ChemicalSpeciesLabel >>>> >>>> SaveRho .true. >>>> >>>> LatticeConstant 1.0 Ang >>>> >>>> %block LatticeParameters >>>> 99.6 99.6 99.6 60. 60. 60. >>>> %endblock LatticeParameters >>>> >>>> %block AtomicCoordinatesOrigin >>>> 0.000 0.000 0.000 >>>> %endblock AtomicCoordinatesOrigin >>>> >>>> >>>> >>>> MD.TypeOfRun CG >>>> MD.NumCGSteps 0 >>>> >>>> AtomicCoordinatesFormat Fractional >>>> >>>> %block AtomicCoordinatesAndAtomicSpecies >>>> 0.000 0.000 0.000 1 >>>> 0.025 0.000 0.000 1 >>>> 0.050 0.000 0.000 1 >>>> 0.075 0.000 0.000 1 >>>> 0.000 0.025 0.000 1 >>>> 0.025 0.025 0.000 1 >>>> 0.050 0.025 0.000 1 >>>> 0.075 0.025 0.000 1 >>>> 0.000 0.050 0.000 1 >>>> 0.025 0.050 0.000 1 >>>> 0.050 0.050 0.000 1 >>>> 0.075 0.050 0.000 1 >>>> 0.000 0.075 0.000 1 >>>> 0.025 0.075 0.000 1 >>>> 0.050 0.075 0.000 1 >>>> 0.075 0.075 0.000 1 >>>> 0.000 0.000 0.025 1 >>>> 0.025 0.000 0.025 1 >>>> 0.050 0.000 0.025 1 >>>> 0.075 0.000 0.025 1 >>>> 0.000 0.025 0.025 1 >>>> 0.025 0.025 0.025 1 >>>> 0.050 0.025 0.025 1 >>>> 0.075 0.025 0.025 1 >>>> 0.000 0.050 0.025 1 >>>> 0.025 0.050 0.025 1 >>>> 0.050 0.050 0.025 1 >>>> 0.075 0.050 0.025 1 >>>> 0.000 0.075 0.025 1 >>>> 0.025 0.075 0.025 1 >>>> 0.050 0.075 0.025 1 >>>> 0.075 0.075 0.025 1 >>>> 0.000 0.000 0.050 1 >>>> 0.025 0.000 0.050 1 >>>> 0.050 0.000 0.050 1 >>>> 0.075 0.000 0.050 1 >>>> 0.000 0.025 0.050 1 >>>> 0.025 0.025 0.050 1 >>>> 0.050 0.025 0.050 1 >>>> 0.075 0.025 0.050 1 >>>> 0.000 0.050 0.050 1 >>>> 0.025 0.050 0.050 1 >>>> 0.050 0.050 0.050 1 >>>> 0.075 0.050 0.050 1 >>>> 0.000 0.075 0.050 1 >>>> 0.025 0.075 0.050 1 >>>> 0.050 0.075 0.050 1 >>>> 0.075 0.075 0.050 1 >>>> 0.000 0.000 0.075 1 >>>> 0.025 0.000 0.075 1 >>>> 0.050 0.000 0.075 1 >>>> 0.075 0.000 0.075 1 >>>> 0.000 0.025 0.075 1 >>>> 0.025 0.025 0.075 1 >>>> 0.050 0.025 0.075 1 >>>> 0.075 0.025 0.075 1 >>>> 0.000 0.050 0.075 1 >>>> 0.025 0.050 0.075 1 >>>> 0.050 0.050 0.075 1 >>>> 0.075 0.050 0.075 1 >>>> 0.000 0.075 0.075 1 >>>> 0.025 0.075 0.075 1 >>>> 0.050 0.075 0.075 1 >>>> 0.075 0.075 0.075 1 >>>> 0.000 0.000 0.100 1 >>>> 0.025 0.000 0.100 1 >>>> 0.050 0.000 0.100 1 >>>> 0.075 0.000 0.100 1 >>>> 0.000 0.025 0.100 1 >>>> 0.025 0.025 0.100 1 >>>> 0.050 0.025 0.100 1 >>>> 0.075 0.025 0.100 1 >>>> 0.000 0.050 0.100 1 >>>> 0.025 0.050 0.100 1 >>>> 0.050 0.050 0.100 1 >>>> 0.075 0.050 0.100 1 >>>> 0.000 0.075 0.100 1 >>>> 0.025 0.075 0.100 1 >>>> 0.050 0.075 0.100 1 >>>> 0.075 0.075 0.100 1 >>>> 0.033 0.033 0.125 2 >>>> 0.100 0.000 0.000 1 >>>> 0.100 0.025 0.000 1 >>>> 0.100 0.050 0.000 1 >>>> 0.100 0.075 0.000 1 >>>> 0.100 0.100 0.000 1 >>>> 0.100 0.000 0.025 1 >>>> 0.100 0.025 0.025 1 >>>> 0.100 0.050 0.025 1 >>>> 0.100 0.075 0.025 1 >>>> 0.100 0.100 0.025 1 >>>> 0.100 0.000 0.050 1 >>>> 0.100 0.025 0.050 1 >>>> 0.100 0.050 0.050 1 >>>> 0.100 0.075 0.050 1 >>>> 0.100 0.100 0.050 1 >>>> 0.100 0.000 0.075 1 >>>> 0.100 0.025 0.075 1 >>>> 0.100 0.050 0.075 1 >>>> 0.100 0.075 0.075 1 >>>> 0.100 0.100 0.075 1 >>>> 0.100 0.000 0.100 1 >>>> 0.100 0.025 0.100 1 >>>> 0.100 0.050 0.100 1 >>>> 0.100 0.075 0.100 1 >>>> 0.100 0.100 0.100 1 >>>> 0.000 0.100 0.000 1 >>>> 0.025 0.100 0.000 1 >>>> 0.050 0.100 0.000 1 >>>> 0.075 0.100 0.000 1 >>>> 0.000 0.100 0.025 1 >>>> 0.025 0.100 0.025 1 >>>> 0.050 0.100 0.025 1 >>>> 0.075 0.100 0.025 1 >>>> 0.000 0.100 0.050 1 >>>> 0.025 0.100 0.050 1 >>>> 0.050 0.100 0.050 1 >>>> 0.075 0.100 0.050 1 >>>> 0.000 0.100 0.075 1 >>>> 0.025 0.100 0.075 1 >>>> 0.050 0.100 0.075 1 >>>> 0.075 0.100 0.075 1 >>>> 0.000 0.100 0.100 1 >>>> 0.025 0.100 0.100 1 >>>> 0.050 0.100 0.100 1 >>>> 0.075 0.100 0.100 1 >>>> %endblock AtomicCoordinatesAndAtomicSpecies >>>> >>>> SolutionMethod diagon >>>> >>>> >>>> >>>> >>>> >>>> Thnx in advance!! >>>> >>>> >> >
