Dear QE developers, I have a question about optimization of a hcp structure (e.g. Ti and Zr). Any hcp structure have two lattice constants (a and c), so for scf calculation, it is nessesry to optimize both lattice constants.
Method 1: Fixed celldm(3) at ideal c/a ratio (1.633) and then changed celldm(1)=a and eventually computation of total energy. Method 2: Fixed celldm(1) at experimental lattice constant and then changed celldm(3)=c/a and computing of total energy. Method 3: Fixed unit cell volume at experimental volume and then changed c/a ratio and calculation of a (Volume=fixed) and run scf calculation with different a and c/a. what is best method for optimization of a and c? Method 1, 2 , 3 or others method? I am very thankful any to help me. -- Romeda Azeen, Bhavnagar University Bhavnagar 364002 Gujarat India -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120331/fedc72fb/attachment.htm
