mirror of https://gitlab.com/QEF/q-e.git
79 lines
2.1 KiB
Fortran
79 lines
2.1 KiB
Fortran
!
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! Copyright (C) 2001-2007 Quantum ESPRESSO group
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! This file is distributed under the terms of the
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! GNU General Public License. See the file `License'
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! in the root directory of the present distribution,
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! or http://www.gnu.org/copyleft/gpl.txt .
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!
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subroutine addcore (mode, drhoc)
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!
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! This routine computes the change of the core charge
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! when the atoms moves along the given mode
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!
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!
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USE kinds, only : DP
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use uspp_param, only : upf
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use ions_base, only : nat, ityp
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use cell_base, only : tpiba
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use fft_base, only : dfftp
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use fft_interfaces, only: invfft
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use gvect, only : ngm, mill, eigts1, eigts2, eigts3, g
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use modes, only : u
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use qpoint, only : eigqts, xq
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use nlcc_ph, only : drc
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use uspp, only : nlcc_any
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implicit none
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!
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! The dummy variables
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!
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integer, intent (IN) :: mode
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! input: the mode
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complex(DP), intent(OUT) :: drhoc (dfftp%nnr)
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! output: the change of the core charge
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!
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! Local variables
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!
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integer :: nt, ig, mu, na
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complex(DP) :: fact, gu, gu0, u1, u2, u3, gtau
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!
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!
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if (.not.nlcc_any) return
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!
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! compute the derivative of the core charge along the given mode
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!
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drhoc(:) = (0.d0, 0.d0)
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do na = 1, nat
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nt = ityp (na)
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if (upf(nt)%nlcc) then
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fact = tpiba * (0.d0, -1.d0) * eigqts (na)
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mu = 3 * (na - 1)
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if ( abs (u (mu + 1, mode) ) + &
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abs (u (mu + 2, mode) ) + &
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abs (u (mu + 3, mode) ) > 1.0d-12) then
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u1 = u (mu + 1, mode)
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u2 = u (mu + 2, mode)
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u3 = u (mu + 3, mode)
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gu0 = xq (1) * u1 + xq (2) * u2 + xq (3) * u3
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do ig = 1, ngm
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gtau = eigts1 (mill (1,ig), na) * eigts2 (mill (2,ig), na) &
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* eigts3 (mill (3,ig), na)
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gu = gu0 + g (1, ig) * u1 + g (2, ig) * u2 + g (3, ig) &
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* u3
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drhoc (dfftp%nl (ig) ) = drhoc (dfftp%nl (ig) ) + drc (ig, nt) * gu * &
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fact * gtau
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enddo
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endif
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endif
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enddo
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!
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! transform to real space
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!
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CALL invfft ('Rho', drhoc, dfftp)
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!
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return
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end subroutine addcore
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