ADAS Subroutine cxtbex

      SUBROUTINE CXTBEX( MXNSHL , IZ1    , NBOT   , NTOP   ,
     &                   NGRND  , TEV    , TBQEX  , QTHEX  ,
     &                   FTHEX
     &                 )
C
C
C-----------------------------------------------------------------------
C
C  ****************** FORTRAN77 SUBROUTINE: CXTBEX *********************
C
C  PURPOSE:  SETS UP A TABLE OF ELECTRON IMPACT EXCITATION RATE
C            COEFFICIENTS FOR A HYDROGENIC ION FROM THE GROUND STATE
C            TO EXCITED NL-LEVELS.
C
C  CALLING PROGRAM: ADAS308 , C6TBEX.
C
C  INPUT : (I*4)  MXNSHL   = MAXIMUM VALUE OF N QUANTUM NUMBER.
C  INPUT : (I*4)  IZ1      = ION CHARGE.
C  INPUT : (I*4)  NBOT     = MINIMUM PRINCIPAL QUANTUM NUMBER.
C  INPUT : (I*4)  NTOP     = MAXIMUM PRINCIPAL QUANTUM NUMBER.
C  INPUT : (I*4)  NGRND    =
C  INPUT : (R*8)  TEV      = ELECTRON TEMPERATURE.
C                            UNITS: EV
C
C  OUTPUT: (R*8)  TBQEX()  = TABLE OF NL-LEVEL EXCITATION RATE
C                            COEFFICIENTS.
C                            UNITS:
C                            DIMENSION: REFERENCED BY FUNC I4IDFL(N,L).
C  OUTPUT: (R*8)  QTHEX()  = TABLE OF N-LEVEL EXCITATION RATE
C                            COEFFICIENTS.
C                            UNITS:
C                            DIMENSION: N-SHELL
C  OUTPUT: (R*8)  FTHEX()  = TABLE OF NL-LEVEL EXCITATION RATE
C                            COEFFICIENTS EXPRESSED AS FRACTION OF
C                            CORRESPONDING N-LEVEL RATE.
C                            DIMENSION: REFERENCED BY FUNC I4IDFL(N,L).
C
C  PARAM : (I*4)  MXN      = 'MXNSHL'.
C  PARAM : (R*8)  P1       =
C
C          (I*4)  N        = N QUANTUM NUMBER.
C          (I*4)  L        = L QUANTUM NUMBER.
C          (I*4)  IDL      = L-RESOLVED TABLE INDEX.
C
C          (R*8)  ATE      =
C          (R*8)  RDE      =
C          (R*8)  ETE      =
C          (R*8)  FACT     =
C
C          (R*8)  GAMA()   = TABLE OF EXCITATION RATE PARAMETERS.
C                            UNITS:
C                            DIMENSION: REFERENCED BY N QUANTUM NUMBER.
C
C ROUTINES:
C          ROUTINE    SOURCE    BRIEF DESCRIPTION
C          -------------------------------------------------------------
C          I4UNIT     ADAS      RETURNS UNIT NO. FOR OUTPUT OF MESSAGES.
C          I4IDFL     ADAS      RETURNS UNIQUE INDEX GIVEN QUANTUM
C                               NUMBERS N AND L.
C          CXGHNL     ADAS      CALCULATES EXCITATION RATE PARAMETERS.
C
C AUTHOR:   JONATHAN NASH (TESSELLA SUPPORT SERVICES PLC)
C           K1/0/81
C           JET EXT. 5183
C
C DATE:     05/10/93
C
C-----------------------------------------------------------------------
C
C-----------------------------------------------------------------------
      INTEGER             IZ1,         MXNSHL,      NBOT,        NGRND
      INTEGER             NTOP
      REAL*8              FTHEX((MXNSHL*(MXNSHL+1))/2)
      REAL*8              QTHEX(MXNSHL)
      REAL*8              TBQEX((MXNSHL*(MXNSHL+1))/2),          TEV