mirror of https://gitlab.com/QEF/q-e.git
45 lines
1.4 KiB
Fortran
45 lines
1.4 KiB
Fortran
!
|
|
! Copyright (C) 2004 PWSCF 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 .
|
|
!
|
|
function sph_ind(l,j,m,spin)
|
|
! This function calculates the m index of the spherical harmonic
|
|
! in a spinor with orbital angular momentum l, total angular
|
|
! momentum j, projection along z of the total angular momentum m+-1/2.
|
|
! Spin selects the up (spin=1) or down (spin=2) coefficient.
|
|
!
|
|
use upf_kinds, only: dp
|
|
implicit none
|
|
|
|
integer :: sph_ind
|
|
integer :: l, & ! orbital angular momentum
|
|
m, & ! projection of the total angular momentum+-1/2
|
|
spin ! 1 or 2 select the component
|
|
|
|
real(DP) :: j ! total angular momentum
|
|
|
|
if (spin.ne.1.and.spin.ne.2) call upf_error('sph_ind','spin direction unknown',1)
|
|
if (m.lt.-l-1.or.m.gt.l) call upf_error('sph_ind','m not allowed',1)
|
|
|
|
if (abs(j-l-0.5d0).lt.1.d-8) then
|
|
if (spin.eq.1) sph_ind= m
|
|
if (spin.eq.2) sph_ind= m+1
|
|
elseif (abs(j-l+0.5d0).lt.1.d-8) then
|
|
if (m.lt.-l+1) then
|
|
sph_ind=0
|
|
else
|
|
if (spin.eq.1) sph_ind= m-1
|
|
if (spin.eq.2) sph_ind= m
|
|
endif
|
|
else
|
|
write(6,*) l, j
|
|
call upf_error('sph_ind','l and j not compatible',1)
|
|
endif
|
|
if (sph_ind.lt.-l.or.sph_ind.gt.l) sph_ind=0
|
|
|
|
return
|
|
end function sph_ind
|