Hi Mousumi, > 1. Presently I'm doing some spin-plarized relaxation calculations using > only the option "SpinPolarized yes". But, I will like to do the > calculations with fixed spins on each atom. How to fix spins in SIESTA and > run relax/scf calculations?
Check the flags FixSpin, TotalSpin and DM.InitSpin, in the siesta manual. I guess they will do what you want. > > 2. I need to calculate magnetic moment and spin-dependent electronic DOS > of my system of study after fixing the spins properly. Could someone guide > as to how we calculate magnetic moment in SIESTA. An input file and, > output file will be very helpful. Either I haven't understood what you want, or I am very wrong; but if you fix the spins on the atoms, you have already determined the magnetic moment beforehand, haven't you? The magnetic moment is given at the end of your calculation by Qup-Qdown. With regards to the spin-dependent DOS, you can calculate it in two ways. One of them is using the eig2dos.f program, in the Util directory of siesta. It will calculate the DOS from the eigenvalues, contained in the EIG file. Another one, more expensive, but good if you want to see the constributions of different orbitals and even from individual atoms, is to calculate the Projected Density of States (check for the flag ProjectedDensityOfStates in the manual). It will calculate the PDOS **and** DOS. Since we are speaking of noncollinear spin calculations, I would like to call the developers' attention to a bug in the noncollinear spin calculations. I was doing some tests for noncollinear spin calculations, and I ran into two bugs. One happens in parallel runs, the other in serial runs. Before anything, my compilations: 1) Parallel: compiler: ifort 9, mpich - myrinet version at CINECA and also my own compiled latest version in a dual-core turion -, mpi scalapack and blacs compiled from scratch. Also the latest version of scalapack, 1.8, which I compiled and tested a few minutes ago at CINECA. Intel serial mkl libraries - CINECA doesn't seem to have the cluster version of the mkl. 2) Serial: ifort 9 and mkl. Both versions of siesta are compiled with -DWXML_INIT_FIX flag. The bug in parallel runs is one that has come up so many times in the list, the "error in Cholesky factorization", in cdiag.f . It happens for the prosaic molecule O2, but also happens for the (also prosaic) ptn with 2 atoms in the unit cell. I have not tried running it for a larger system. The Cholesky error disappears when I run the calculations with a fully serial version of siesta, compiled without mpi, scalapack and so on. However, it crashes when, at the end of the first SCF step, it tries to write the data to the xml file. It says that a certain unit is already open, and stops there. I'll be glad to provide all pseudo, fdf and makefiles, plus the procedures I used to compile each of the versions, if this is necessary to reproduce the mistake. Cheers, Marcos -- Dr. Marcos Verissimo Alves Post-Doctoral Fellow Condensed Matter and Statistical Physics Sector International Centre for Theoretical Physics Trieste, Italy -------- I have become so addicted to vi that I try to exit OpenOffice by typing :wq!
