SUBROUTINE surface(v,rij)
!-----------------------------------------------------------------------
! This routine supplies the potential energy surface for the
! reactive scattering codes.
!
! On entering: The array rij contains the internuclear distances
!              in units of bohr (NOT mass scaled).
!
!              The common /pes/ must contain a character string
!              of length 20 that properly describes the potential.
!
! On Exit:     The variable v is the value of the potential energy
!              surface in Hartree atomic units.
!
!
!-----------------------------------------------------------------------
USE PES_Module
implicit none
dimension rij(3)
real*8 v, rij
character(LEN=25) potname_gr, potname_ex
external h2ogr, h2oex
!-----------------------------------------------------------------------
!  The character string potname must contain a string that uniquely
!  specifies the potential energy surface to be used.
!-----------------------------------------------------------------------
data potname_gr/'H2O GROUND STATE PES'/
data potname_ex/'H2O (1B1)  STATE PES'/
!-----------------------------------------------------------------------
! Check for correct potential energy surface specification.
!-----------------------------------------------------------------------
if(PES_Name==potname_gr)then
  call h2ogr(v,rij)
ELSEIF(PES_Name==potname_ex)then
  call h2oex(v,rij)
ELSE
  write(6,*)'The potential energy surface name does not match', &
            ' the name in the potential energy surface routine.'
  write(6,*)'***error***: Execution stopped in routine surface'
  stop 'potname'
endif
!-----------------------------------------------------------------------
! This call to surface supplies the potential energy surface
! for the particular system of interest.
!-----------------------------------------------------------------------
return
ENDSUBROUTINE Surface