Dear All, Thank you very much for your time!
I am puzzled about the set of LatticeVectors in the input file. Maybe the fellow question is too simple, but it's really a problem for me to understand it. For example, when you do a bulk calculation of Au leads (111). What do you think the difference between the different set of lattice vectors, set as follow. one: %block LatticeVectors 9.571313000 0.000000000 0.0000000000 0.000000000 14.01989100 0.0000000000 0.000000000 0.000000000 7.0691600000 %endblock LatticeVectors second: %block LatticeVectors 4.3289600000 -8.4979700000 0.0000000000 4.3289600000 8.4979700000 0.0000000000 0.0000000000 0.0000000000 7.0691600000 %endblock LatticeVectors As we known that the Au is FCC, it seems that the second choice is better. But as in some case, we select some part of system, for example Au, to represent the period structure of bulk system. What's the physical view of this kind? Could you give some explain? Thank you very much in advace! Jackie Wan, The input file: ============================================= # Sample file for programs SIESTA SystemName Au-lead # Descriptive name of the system SystemLabel Au # Short name for naming files NumberOfAtoms 27 # Number of atoms NumberOfSpecies 1 # Number of species PAO.BasisType split # Type of basis ('nones', 'nonodes', 'split') PAO.SplitNorm 0.15 # Amount of norm carried by the second zeta %block ChemicalSpeciesLabel 1 79 Au %endblock ChemicalSpeciesLabel %block PAO.Basis Au 1 n=6 0 1 6.0 %endblock PAO.Basis LatticeConstant 1.0 Ang %block LatticeVectors 4.3289600000 -8.4979700000 0.0000000000 4.3289600000 8.4979700000 0.0000000000 0.0000000000 0.0000000000 7.0691600000 %endblock LatticeVectors AtomicCoordinatesFormat Ang %block AtomicCoordinatesAndAtomicSpecies 1.4429860000 0.8331080000 0.0000000000 1 2.8859710000 -1.6662140000 0.0000000000 1 4.3289560000 -4.1655360000 0.0000000000 1 2.8859710000 3.3324300000 0.0000000000 1 4.3289560000 0.8331080000 0.0000000000 1 5.7719410000 -1.6662140000 0.0000000000 1 4.3289560000 5.8317520000 0.0000000000 1 5.7719410000 3.3324300000 0.0000000000 1 7.2149260000 0.8331080000 0.0000000000 1 1.4429860000 -0.8331080000 2.3563870000 1 2.8859710000 -3.3324300000 2.3563870000 1 4.3289560000 -5.8317520000 2.3563870000 1 2.8859710000 1.6662140000 2.3563870000 1 4.3289560000 -0.8331080000 2.3563870000 1 5.7719410000 -3.3324300000 2.3563870000 1 4.3289560000 4.1655360000 2.3563870000 1 5.7719410000 1.6662140000 2.3563870000 1 7.2149260000 -0.8331080000 2.3563870000 1 0.0000000000 0.0000000000 4.7127680000 1 1.4429850000 -2.4993220000 4.7127680000 1 2.8859700000 -4.9986440000 4.7127680000 1 1.4429850000 2.4993220000 4.7127680000 1 2.8859700000 0.0000000000 4.7127680000 1 4.3289550000 -2.4993220000 4.7127680000 1 2.8859700000 4.9986440000 4.7127680000 1 4.3289550000 2.4993220000 4.7127680000 1 5.7719400000 0.0000000000 4.7127680000 1 %endblock AtomicCoordinatesAndAtomicSpecies %block kgrid_Monkhorst_Pack 2 0 0 0.0 0 2 0 0.0 0 0 3 0.0 %endblock kgrid_Monkhorst_Pack BandLinesScale ReciprocalLatticeVectors xc.functional GGA # 'LDA', 'GGA' xc.authors PBE #'CA'='PZ', 'PW92', 'PBE' SpinPolarized F # 'T', 'F' FixSpin F TotalSpin 0.0 NonCollinearSpin F # 'T', 'F' MeshCutoff 180. Ry # Equivalent plane wave cutoff for the grid MaxSCFIterations 300 DM.MixingWeight 0.05 DM.Tolerance 1.0E-5 NeglNonOverlapInt T # 'F'=do not neglect SolutionMethod diagon ElectronicTemperature 300 K # Default value ============================================== end of input file