!
! Copyright (C) 2004-2007 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 .
!
! ------------------------------------------------------------------
function atomic_number(atm)
  ! ------------------------------------------------------------------
  !
  implicit none
  character(len=*) :: atm
  integer :: atomic_number

  character(len=2) :: elements(103), atom
  data elements/' H',                              'He', &
                'Li','Be',' B',' C',' N',' O',' F','Ne', &
                'Na','Mg','Al','Si',' P',' S','Cl','Ar', &
                ' K','Ca','Sc','Ti',' V','Cr','Mn',      &
                          'Fe','Co','Ni','Cu','Zn',      &
                          'Ga','Ge','As','Se','Br','Kr', &
                'Rb','Sr',' Y','Zr','Nb','Mo','Tc',      &
                          'Ru','Rh','Pd','Ag','Cd',      &
                          'In','Sn','Sb','Te',' I','Xe', &
                'Cs','Ba','La','Ce','Pr','Nd','Pm','Sm','Eu','Gd', &
                               'Tb','Dy','Ho','Er','Tm','Yb','Lu', &
                               'Hf','Ta',' W','Re','Os', &
                          'Ir','Pt','Au','Hg',           &
                          'Tl','Pb','Bi','Po','At','Rn', &
                'Fr','Ra','Ac','Th','Pa',' U','Np','Pu', &
                'Am','Cm','Bk','Cf','Es','Fm','Md','No', 'Lr' /
  character(len=1), external :: capital, lowercase
  logical, external :: isnumeric
  integer :: n

  atom='  '
  if ( len(atm) == 1 ) then
!
! Case : atm='X'
!
     atom(2:2)=capital(atm(1:1))
  else if ( ( len_trim(atm) == 1 ) .or. ( isnumeric(atm(2:2)) ) .or. &
          ( atm(2:2) == '-' )    .or. ( atm(2:2) == '_' ) ) then
!
! Case : atm='X ', 'X_*', 'X-*', 'X[0-9]* '
!
     atom(2:2)=capital(atm(1:1))
  else if (atm(1:1) == ' ') then
!
! Case : atm=' X*'
!
     atom(2:2)=capital(atm(2:2))
  else
!
! Case : atm='XY*'
!
     atom(1:1)=capital(atm(1:1))
     atom(2:2)=lowercase(atm(2:2))
  end if
      
  do n=1, 103
     if ( atom == elements(n) ) then
        atomic_number=n
        return
     end if
  end do

  atomic_number = 0
  print '(''Atom '',a2,'' not found'')', atom
  stop

end function atomic_number
! ------------------------------------------------------------------
function atom_name(atomic_number)
  ! ------------------------------------------------------------------
  !
  integer :: atomic_number
  character(len=2) :: atom_name

  character(len=2) :: elements(103)
  data elements/' H',                              'He', &
                'Li','Be',' B',' C',' N',' O',' F','Ne', &
                'Na','Mg','Al','Si',' P',' S','Cl','Ar', &
                ' K','Ca','Sc','Ti',' V','Cr','Mn',      &
                          'Fe','Co','Ni','Cu','Zn',      &
                          'Ga','Ge','As','Se','Br','Kr', &
                'Rb','Sr',' Y','Zr','Nb','Mo','Tc',      &
                          'Ru','Rh','Pd','Ag','Cd',      &
                          'In','Sn','Sb','Te',' I','Xe', &
                'Cs','Ba','La','Ce','Pr','Nd','Pm','Sm','Eu','Gd', &
                               'Tb','Dy','Ho','Er','Tm','Yb','Lu', &
                               'Hf','Ta',' W','Re','Os', &
                          'Ir','Pt','Au','Hg',           &
                          'Tl','Pb','Bi','Po','At','Rn', &
                'Fr','Ra','Ac','Th','Pa',' U','Np','Pu', &
                'Am','Cm','Bk','Cf','Es','Fm','Md','No', 'Lr' /

  if (atomic_number < 1 .or. atomic_number > 103) then
     call errore('atom_name','invalid atomic number',1000+atomic_number)
  else
     atom_name=elements(atomic_number)
  end if
  return

end function atom_name

! ------------------------------------------------------------------
function atom_weight(atomic_number)
  ! ------------------------------------------------------------------
  !
  USE kinds, ONLY : DP
  implicit none
  integer :: atomic_number
  real(DP) :: atom_weight

  real(DP) :: weights(103)
  data weights/ 1.00794_DP,                           4.00260_DP, &
                6.941_DP,9.01218_DP,10.811_DP,12.0107_DP,14.00674_DP, &
                15.9994_DP,18.99840_DP,20.1797_DP, &
                22.98977_DP,24.3050_DP,26.98154_DP,28.0855_DP,30.97376_DP, &
                32.066_DP,35.4527_DP,39.948_DP, &
                39.0983_DP,40.078_DP,44.95591_DP,47.867_DP,50.9415_DP, &
                51.9961_DP,54.93805_DP, 55.845_DP,      &
                58.93320_DP,58.6934_DP,63.546_DP,65.39_DP,      &
                69.723_DP,72.61_DP,74.92160_DP,78.96_DP,79.904_DP,83.80_DP, &
                85.4678_DP,87.62_DP,88.90585_DP,91.224_DP,92.90638_DP, &
                95.94_DP,98._DP,      &
                101.07_DP,102.90550_DP,106.42_DP,107.8682_DP,112.411_DP,    &
                114.818_DP,118.710_DP,121.760_DP,127.60_DP,126.90447_DP, &
                131.29_DP, &
                132.90545_DP,137.327_DP,138.9055_DP,140.116_DP,140.90765_DP, &
                144.24_DP,145._DP,150.36_DP,151.964_DP,157.25_DP, &
                158.92534_DP,162.50_DP,164.93032_DP,167.26_DP,   &
                168.93421_DP,173.04_DP,174.967_DP, &
                178.49_DP,180.9479_DP,183.84_DP,186.207_DP,190.23_DP, &
                192.217_DP,195.078_DP,196.96655_DP,200.59_DP,           &
                204.3833_DP,207.2_DP,208.98038_DP,209._DP,210._DP,222._DP, &
                223._DP,226._DP,227._DP,232.0381_DP,231.03588_DP, &
                238.0289_DP,237._DP,244._DP, &
                243._DP,247._DP,247._DP,251._DP,252._DP,257._DP,  &
                258._DP,259._DP, 262._DP /

  if (atomic_number < 1 .or. atomic_number > 103) then
     call errore('atom_name','invalid atomic number',1000+atomic_number)
  else
     atom_weight=weights(atomic_number)
  end if
  return

end function atom_weight
!