ADAS Subroutine r8ecip

      FUNCTION R8ECIP( IZC , XI , ZETA , TE )
C
C
C-----------------------------------------------------------------------
C
C  **************** FORTRAN77 REAL*8 FUNCTION: R8ECIP ******************
C
C  PURPOSE:  CALUCLATES THE SHELL CONTRIBUTION TO THE IONISATION RATE
C            COEFFICIENT IN THE ECIP APPROXIMATION OF BURGESS.
C
C            CF. SUMMERS (1974) APPLETON LABORATORY REPORT IM367.
C
C  CALLING PROGRAM: GENERAL USE
C
C  FUNC:   (R*8)  R8ECIP  = IONISATION RATE COEFFICIENT.
C                           UNITS: CM3 SEC-1
C
C  INPUT : (I*4)  IZC     = TARGET ION CHARGE NUMBER.
C  INPUT : (R*8)  XI      = EFFECTIVE IONISATION POTENTIAL FOR SHELL.
C                           UNITS: RYD
C  INPUT : (R*8)  ZETA    = EFFECTIVE NUMBER OF EQUIVALENT ELECTRONS FOR
C                           SHELL.
C  INPUT : (R*8)  TE      = ELECTRON TEMPERATURE.
C                           UNITS: K
C
C  PARAM : (I*4) MXT      = 5.
C  PARAM : (R*8) P1       =
C
C          (I*4)  J       = LOOP INDEX
C
C          (R*8)  Z       = REAL VALUE = IZC+1.
C          (R*8)  ATE     =
C          (R*8)  EN      =
C          (R*8)  Y       =
C          (R*8)  AI      =
C          (R*8)  B       =
C          (R*8)  B1      =
C          (R*8)  C       =
C          (R*8)  R       =
C          (R*8)  D       =
C          (R*8)  F       =
C          (R*8)  C1      =
C          (R*8)  C2      =
C          (R*8)  C4      =
C
C          (R*8)  X()     =
C          (R*8)  W()     =
C
C ROUTINES:
C          ROUTINE    SOURCE    BRIEF DESCRIPTION
C          -------------------------------------------------------------
C          R8YIP      ADAS
C
C AUTHOR:  JONATHAN NASH (TESSELLA SUPPORT SERVICES PLC)
C          K1/0/81
C          JET EXT. 5183
C
C DATE:    03/11/93
C
C UNIX-IDL PORT:
C
C AUTHOR:  WILLIAM OSBORN (TESSELLA SUPPORT SERVICES PLC)
C
C DATE:    22ND MAY 1996
C
C VERSION: 1.1                          DATE: 22-05-96
C MODIFIED: WILLIAM OSBORN
C               - FIRST VERSION. IBM VERSION NOT CHANGED
C
C VERSION: 1.2                          DATE: 10-04-2007
C MODIFIED : Allan Whiteford
C               - Modified documentation as part of automated
C		  subroutine documentation preparation.
C-----------------------------------------------------------------------
C
C-----------------------------------------------------------------------
      INTEGER             IZC
      REAL*8              TE,          XI,          ZETA