1 2This example shows how to use pw.x to calculate the total energy 3and the band structure of four simple systems (Fe, Al, Cu, Ni, Fe) 4in the non collinear case. 5 6The calculation proceeds as follows (for the meaning of the cited input 7variables see the appropriate INPUT_* file) 8 91) make a self-consistent calculation for Fe (input=fe.scf.in, 10 output=fe.scf.out). The number of computed bands is internally 11 computed as equal to the number of electrons in the unit cell 12 (16 in this case). 13 142) make a band structure calculation for Fe (input=fe.band.in, 15 output=fe.band.out). 16 The variable nbnd is explicitly set = 16. 17 The list of k points given in input is the list of point where the 18 bands are computed, the k-point weight is arbitrary and is not used. 19 203) make a self-consistent calculation for Fe with penalty functional 21 where each component of the magnetization of the two atoms 22 is constrained (input=fe.pen.in, output=fe.pen.out). 23 Iron is a metal : the smearing technique is used for the 24 calculation of the Fermi energy (a value for the broadening 25 degauss is provided). 26 274) make a self-consistent calculation for Fe with penalty functional 28 where the angle between the direction of the magnetization of each atom 29 and the z axis is constrained; mcons(1) = cosine of this angle. 30 (input=fe.angl.in, output=fe.angl.out). 31 325) make a self-consistent calculation for Fe with penalty functional 33 where each component of the total magnetization is constrained; 34 fixed_magnetization(ipol) = value of the magnetization. 35 (input=fe.total.in, output=fe.total.out). 36 376) make a self-consistent calculation for Cu (input=cu.scf.in, 38 output=cu.scf.out). 39 Copper is also a metal. In this case the tetrahedron method is used 40 for the calculation of the Fermi energy. K-points are automatically 41 generated. 42 437) make a band structure calculation for Cu (input=cu.band.in, 44 output=cu.band.out). 45 The variable nbnd is explicitly set = 8. 46 The list of k points given in input is the list of point where the 47 bands are computed, the k-point weight is arbitrary and is not used. 48 498) make a self-consistent calculation for Cu (input=cu.cg.in, 50 output=cu.cg.out) with cg diagonalization. 51 529) make a self-consistent calculation for Cu (input=cu.diis.in, 53 output=cu.diis.out) with diis diagonalization. 54 55 5610) make a self-consistent calculation for Ni (input=ni.scf.in, 57 output=ni.scf.out). 58 Nickel is a magnetic metal. A local-spin-density calculation is 59 performed by specifying nspin=2 and an initial guess for the 60 magnetization of each atomic species. This initial guess is used to 61 build spin-up and spin-down starting charges from superposition of 62 atomic charges. 63 6411) make a band structure calculation for Ni (input=ni.band.in, 65 output=ni.band.out). 66 6712) make a scf calculation of molecular oxygen relaxing the atoms. 68