ADAS Subroutine r8ah

      FUNCTION R8AH ( NU , LU , NL , LL )
C
C
C-----------------------------------------------------------------------
C
C  **************** FORTRAN77 REAL*8 FUNCTION: R8AH   ******************
C
C  PURPOSE: CALCULATES A-VALUES FOR HYDROGEN.
C
C  CALLING PROGRAM: GENERAL USE
C
C  FUNC:   (R*8)  R8AH    = HYDROGEN A-VALUE.
C
C  INPUT:  (I*4)  NU      = UPPER VALUE OF N QUANTUM NUMBER.
C  INPUT:  (I*4)  LU      = UPPER VALUE OF L QUANTUM NUMBER.
C  INPUT:  (I*4)  NL      = LOWER VALUE OF N QUANTUM NUMBER.
C  INPUT:  (I*4)  LL      = LOWER VALUE OF L QUANTUM NUMBER.
C
C  PARAM:  (R*8)  P1      = EQUATION CONSTANT.
C
C          (R*8)  XNU     = REAL VALUE = NU.
C          (R*8)  XLU     = REAL VALUE = LU.
C          (R*8)  XNL     = REAL VALUE = NL.
C          (R*8)  XLL     = REAL VALUE = LL.
C          (R*8)  T1      =
C          (R*8)  DE      =
C
C ROUTINES:
C          ROUTINE    SOURCE    BRIEF DESCRIPTION
C          -------------------------------------------------------------
C          R8RD2B     ADAS      RETURNS HYDRONIC BOUND-BOUND RADIAL
C                               INTEGRAL.
C
C AUTHOR:   JONATHAN NASH (TESSELLA SUPPORT SERVICES PLC)
C           K1/0/81
C           JET EXT. 5183
C
C DATE:     29/09/93
C
C-----------------------------------------------------------------------
C
C-----------------------------------------------------------------------
      INTEGER             LL,          LU,          NL,          NU