quantum-espresso/Gamma/h_h.f90

58 lines
1.5 KiB
Fortran

!
! Copyright (C) 2003-2007 Quantum-ESPRESSO group
! This file is distributed under the terms of the
! GNU General Public License. See the file `License'
! in the root directory of the present distribution,
! or http://www.gnu.org/copyleft/gpl.txt .
!
!
!-----------------------------------------------------------------------
subroutine H_h(e,h,Ah)
!-----------------------------------------------------------------------
#include "f_defs.h"
!
USE kinds, only: DP
USE wvfct, ONLY: nbnd, npwx, npw, g2kin, igk
USE gvect, ONLY : gstart
USE uspp, ONLY : vkb, nkb
USE lsda_mod, ONLY : current_spin
USE scf, ONLY : vrs
use becmod, only: rbecp, calbec
use cgcom
!
implicit none
!
real(DP):: e(nbnd)
complex(DP):: h(npwx,nbnd), Ah(npwx,nbnd)
!
integer:: j,ibnd
!
call start_clock('h_h')
!
! [(k+G)^2 - e ]psi
do ibnd = 1,nbnd
! set to zero the imaginary part of h at G=0
! needed for numerical stability
if (gstart==2) h(1,ibnd) = CMPLX( DBLE(h(1,ibnd)),0.d0)
do j = 1,npw
ah(j,ibnd) = (g2kin(j)-e(ibnd)) * h(j,ibnd)
end do
end do
! V_Loc psi
call vloc_psi(npwx, npw, nbnd, h, vrs(1,current_spin), ah)
! V_NL psi
call calbec ( npw, vkb, h, rbecp )
if (nkb > 0) call add_vuspsi (npwx, npw, nbnd, h, ah)
! set to zero the imaginary part of ah at G=0
! needed for numerical stability
if (gstart==2) then
do ibnd = 1, nbnd
ah(1,ibnd) = CMPLX( DBLE(ah(1,ibnd)),0.d0)
end do
end if
!
call stop_clock('h_h')
!
return
end subroutine H_h