ADAS Subroutine cxlthe

      SUBROUTINE CXLTHE( IZ0 , ZEFF , N , L , E0 )
C
C
C-----------------------------------------------------------------------
C
C  ******************* FORTRAN77 SUBROUTINE: CXLTHE ********************
C
C  PURPOSE:  PROVIDES BINDING ENERGY OF TERM CENTRE FOR OUTER ELECTRON
C            IN LITHIUM LIKE IONS.
C
C            FROM EDLEN (1979) PHYSICA SCRIPTA, 19, 255.
C
C            FINE STRUCTURE FOR L>0 MUST BE ADDED EXTERNALLY.
C
C  CALLING PROGRAM: GENERAL USE
C
C  INPUT : (I*4)  IZ0     = NUCLEAR CHARGE.
C  INPUT : (R*8)  ZEFF    = EFFECTIVE NUCLEAR CHARGE.
C  INPUT : (I*4)  N       = PRINCIPAL QUANTUM NUMBER.
C  INPUT : (I*4)  L       = ORBITAL QUANTUM NUMBER.
C
C  OUTPUT: (R*8)  E0      = BINDING ENERGY.
C                           UNITS: RYD
C
C          (R*8)  Z       = DUMMY ARGUMENT TO STATEMENT FUNCTIONS.
C          (R*8)  F       = DUMMY ARGUMENT TO STATEMENT FUNCTIONS.
C
C          (R*8)  Z0      = REAL VALUE = IZ0.
C          (R*8)  XN      = REAL VALUE = N.
C          (R*8)  XL      = REAL VALUE = L.
C          (R*8)  R       =
C          (R*8)  RC      =
C          (R*8)  T1      =
C          (R*8)  T2      =
C          (R*8)  T3      =
C          (R*8)  T4      =
C          (R*8)  A       =
C          (R*8)  B       =
C          (R*8)  C       =
C          (R*8)  T2S     =
C          (R*8)  D2S     =
C          (R*8)  T2P1    =
C          (R*8)  T2P2    =
C          (R*8)  T2P     =
C          (R*8)  D2P     =
C          (R*8)  U       =
C          (R*8)  U0      =
C          (R*8)  V       =
C          (R*8)  TNL     =
C          (R*8)  S       =
C          (R*8)  AK      =
C          (R*8)  DP      =
C
C ROUTINES:
C          ROUTINE    SOURCE    BRIEF DESCRIPTION
C          -------------------------------------------------------------
C          I4UNIT     ADAS      RETURNS UNIT NO. FOR OUTPUT OF MESSAGES.
C          R8P        ADAS
C          R8QP       ADAS
C          EL0        INTERNAL
C          SIG0       INTERNAL
C          DRS        INTERNAL
C          DRP        INTERNAL
C          DLS        INTERNAL
C          DLP        INTERNAL
C
C AUTHOR:  JONATHAN NASH (TESSELLA SUPPORT SERVICES PLC)
C          K1/0/81
C          JET EXT. 5183
C
C DATE:    02/11/93
C
C-----------------------------------------------------------------------
C
C-----------------------------------------------------------------------
      INTEGER             IZ0,         L,           N
      REAL*8              E0,          ZEFF