REAL(Kind=WP_Kind) FUNCTION VNENE(rnene)
USE Numeric_Kinds_Module
!  original Aziz-Slaman routine used reduced units.  This version has
!  r and v in atomic units.  Russ Pack 98/5/5
IMPLICIT NONE
REAL(Kind=WP_Kind) epsnene, rmnene, x, x2, x6, x8, x10, rnene, ua, a, ub, b
REAL(Kind=WP_Kind) alpha, beta, uc, c6, c8, c10, d1x, chnge, en, d, ud, c, em
INTEGER icall
CHARACTER(LEN=21), PARAMETER:: ProcName='vnene   '
!  ------1---------2---------3---------4---------5---------6---------7--
COMMON/POTNENE/A,ALPHA,C6,C8,C10,C,D,CHNGE,B,BETA,EN,EM
data icall /0/
SAVE
!  determine parameters on first CALL.
IF(icall==0)THEN
   CALL nenedat
!  well depth and rm, both in au.
   epsnene = 1.337985194d-04
   rmnene = 5.841143031d0
   icall=1
ENDIF
!  start here on further calls
vnene = 0.d0
x = rnene/rmnene
IF(x>1.d04) RETURN
X2=X*X
X6=X2**3
X8=X2*X6
X10=X8*X2
UA=A
UB=ALPHA*X-BETA*X*X
UC=C6/X6+C8/X8+C10/X10
D1X=D/X-1.D0
UD=DEXP(-DMIN1(174.D0,C*D1X*D1X))
IF(X>=CHNGE)THEN
   VNENE=UA*DEXP(-DMIN1(174.D0,UB))-UC
ELSE
   VNENE=UA*DEXP(-DMIN1(174.D0,UB))-UC*UD
ENDIF
vnene = epsnene*vnene
RETURN
END