Dear Matteo, Thank you so much for your explanatory response. The very essence of my question is as follows: If I want to add a term or a constant to the Hamiltonian of a given system, which subroutine or code (*.f90) must be modified?
On Nov 14, 2016 12:02 PM, "Matteo Cococcioni" <[email protected]> wrote: > Dear Ashkan, > > I'm not sure I understand your question completely, but will attempt an > answer. > > First thing to keep in mind is that QE (as any other DFT code) works with > the Kohn-Sham single particle Hamiltonian (is that what you are looking > for?), whose eigenstates are the ones that allow you to construct the > ground state charge density of a system and to evaluate its total energy. > Due to the Bloch theorem (i.e. to the translational invariance of > crystalline solids) this Hamiltonian is block-diagonal on the k-points > (crystal momentum of electrons). Also, QE uses an expansion of Kohn-Sham > wavefunctions on a plane-wave basis set. So, each of these blocks of the > Hamiltonian is npw x npw where npw is the number of plane-waves used in the > expansion of the wavefunctions of that specific k-point. QE performs an > iterative diagonalization of each block that is involves computing the > action of the Hamiltonian onto the current wavefunction H |psi>. This is > done in a routine called h_psi which is the driver to compute various parts > of the Hamiltonian and to operate it on the wavefunction. So I guess you > can look inside that routine in order to find what you need. > > Best regards, > > Matteo > > On Sun, Nov 13, 2016 at 11:24 PM, ashkan shekaari <[email protected]> > wrote: > >> Dear experts, >> >> How, could one derive the Hamiltonian of a given system resulting in >> energy eigenvalues (band structure) *through the modules or subroutines* >> included in Q. E. integrated suite? >> >> Is there anyway for this end? >> >> For example, if I provide an input scf file, how could I figure out what >> Hamiltonian will be used in my calculations? >> >> How could I make a change in the Hamiltonian of a system by manipulating >> subroutines (not the input file)? >> >> >> *--* >> *Regards,* >> *Ashkan Shekaari* >> *Plasma Physics Research Center* >> *Science and Research Branch* >> *I A U, 14778-93855 Tehran, Iran.* >> >> _______________________________________________ >> Pw_forum mailing list >> [email protected] >> http://pwscf.org/mailman/listinfo/pw_forum >> > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
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