How to inter the MAGMOM tag in a noncollinear calculation?

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mxiangying · #1 Post by **mxiangying** » Sat Aug 20, 2011 3:04 pm

Hello all,

I'm attempting a noncollinear calculation with a large number of atoms (120). After a non-magnetic calculation, I added in the INCAR file as:

LNONCOLLINEAR = .TRUE.
MAGMOM = 72*0 0 0 24*8 0 0 24*-8 0 0 #(To avoid too long characters)

Unfortunately, when I try this, it fails and gives the following in the log file:

vasp.5.2.2 15Apr09 complex
POSCAR found : 3 types and 120 ions
Error reading item 'MAGMOM' from file INCAR.
Error code was IERR=0 ... . Found N= 126 data.

How can I deal with it?

Thank you,

Dream

boris · #2 Post by **boris** » Mon Aug 22, 2011 7:26 pm

Hi

72* 0 0 0 is read as : 72*0 then 0 and 0, and not 72*(0,0,0).

So I guess the only way is to write all triplets.

seniyajw · #3 Post by **seniyajw** » Tue Aug 23, 2011 9:40 am

I will work together on a blog this weekend with the source code. Do you use Python, too? I'm just trying to learn Erlang and then plan to do more with her in the future, but so many good tools already exist for mathematics and science in Python.

jlbettis · #4 Post by **jlbettis** » Thu Aug 25, 2011 8:04 pm

Consider 2 atoms, Atom1: is magnetic with 3 unpaired electrons. and atom 2 is nonmagnetic, the Corresponding MAGMOM line, when LNONCOLLINEAR = .TRUE. and SAXIS = 0 0 1, could resemble:

MAGMOM = 0 0 3 3*0
SAXIS = 0 0 1

Above, The SAXIS is defined parallel to the z-axis. The MAGMOM line orients Atom 1's magnetic moment parallel to the z-axis. Non-Collinear calculations require 3 coordinates x,y, and z to be defined in the MAGMOM line. Therefore, Atom 2 which is non-magnetic requires zeros for all three coordinates, This expression is simplified by typing 3*0. If boths atoms were nonmagnetic then the MAGMOM line could read as: MAGMOM = 6*0 .