SUBROUTINE Surface(v,rij)
USE Numeric_Kinds_Module
USE FileUnits_Module
USE PES_MODULE
IMPLICIT NONE
!-----------------------------------------------------------------------
! 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).
!
! On Exit:     The variable v is the value of the potential energy
!              surface in Hartree atomic units.
!
!
!-----------------------------------------------------------------------
REAL(KIND=WP_Kind) rij(3), v
EXTERNAL H3PK
CHARACTER(LEN=25) potname
!-----------------------------------------------------------------------
!  The character string potname must contain a string that uniquely
!  specifies the potential energy surface to be used.
!-----------------------------------------------------------------------
DATA potname/'H3 Porter-Karplus PES    '/
!-----------------------------------------------------------------------
! Check for correct potential energy surface specification.
!-----------------------------------------------------------------------
IF(PES_Name/=potname)THEN
   WRITE(Out_Unit,*)'The potential energy surface name ', 'does not match', &
                    ' the name in the potential energy surface routine.'
   WRITE(Out_Unit,'(1x,2a25)')PES_Name,potname
   WRITE(Out_Unit,*)'***error***: Execution stopped in ', 'routine surface'
   STOP "Surface"
ENDIF
!-----------------------------------------------------------------------
! This call to surfac supplies the potential energy surface
! for the particular system of interest.
!-----------------------------------------------------------------------
CALL H3PK(v,rij)
RETURN
ENDSUBROUTINE Surface