[Wien] relaxation

[Tomas Kana]

Dear Shalika, 

Alternatively, you may use the package OrthoOpt 
available at 
http://susi.theochem.tuwien.ac.at/reg_user/unsupported/OrthoOpt/
This package automatically determines the orthorhombic or monoclinic 
lattice parameters a,b,c (the monoclinic angle is fixed). 
You can try this for several values of the monoclinic angle 
and optimize the angle in this way. The a,b,c will be optimized 
automatically, too.
Tomas 

See option "[7] VARY A, B, C and Gamma (4D-case) (monoclinic lattice)" 
in section "5.3.1 Lattice parameters (Volume, c/a, lattice parameters)" 
on page 74 of the WIEN2k 17.1 usersguide [ 
http://susi.theochem.tuwien.ac.at/reg_user/textbooks/usersguide.pdf ].

Since there are so many degrees of freedom (is a calculation for 4 
dimensions), the calculation is likely very computational expensive.  
Hopefully you have a cluster with many cores.

That should be just lattice parameter optimization.  If atomic position 
optimization is need as well, that may require even more computation.  
The "Structure optimization-notes (pdf)" on the textbook page [ 
http://susi.theochem.tuwien.ac.at/reg_user/textbooks/ ], I think 
describes simultaneous optimization of lattice parameters and atomic 
positions with a simpler case as an example pretty well.

On 9/18/2017 5:49 AM, Shalika R. Bhandari wrote:
  Hi sir,
  I want to learn the steps  optimisation of monoclinic crystal ?