Dear QE users I am calculating the bulk modulus using the ev.x executable. The bulk modulus obtained is extremely sensitive to the number of data i use in the lattice parameter vs energy table. if i use three values a-x, a, a+x, where a is the equilibrium lattice parameter and x is 0.01 or 0.02 bohr the value of bulk modulus is very high as compared to i use 5 or 10 data. Bulk modulus is the double derivative if energy w.r.t. equilibrium lattice parameter. What should be the best method to obtain the bulk modulus of the system. Also if you can provide any tutorial or help to calculate other elastic constant it will be extremely helpful.
Vicky Singh RA, Bangalore -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20140306/725dab85/attachment.html
