[Wien] Large forces appeared when calculating total energy after structure optimization

[shamik chakrabarti]

Dear Wien2k users,
                                I have initially optimized an orthorhombic
crystal system structurally (simultaneous optimization of a,b,c &
coordinates & then optimization of coordinates again by taking optimized
lattice parameters). However, after taking the optimized structure when I
simulate the total energy with converged SCFby running the command
runsp_lapw -dm -orb -fc 1.0 -ec 0.0001 -cc 0.0001, I have found that large
forces ~ 40 mRy/a.u.  appeared for few atoms.

My queries are (a) why this happens? & (b) what is the remedy? (c) whether
DOS is reliable in this case?


*However, the simulated voltage as calculated from the total energy of the
system has been matched with the experiment very well. *

Looking forward to hearing from you.

with regards,
-- 
Dr. Shamik Chakrabarti
Research Fellow
Department of Physics
Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India
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