[DFTB-Plus-User] Correct handling of lattice parameters (Monoclinic, Tetragonal)

[Husak Michal]

I see my previous E-mail was added to incorrect thread ...


Question:

How to handle correctly in DFTB+ crystals with a lattice with given lattice parameters restriction (when the cell is optimized).

Examples:

Monoclinic = parameter beta needs to be fixed to 90

Tetragonal = a should be equal to b

e.t.c.


Current version of DFBT+ makes possible only to fix ALL angles , not each one individually ...

It does not make possible to give expression between lattice vectors length (e.g. a=b) as well ...


Without this future calculation of crystals with known crystal system can not be done correctly ...


Michal Husak

UCT Prague