ADAS Subroutine i4ngrp

      FUNCTION I4NGRP(CHR)
C
C---------------------------------------------------------------------
C
C  ****************** FORTRAN77 FUNCTION: I4NGRP  ********************
C
C  PURPOSE: RETURNS N QUANTUM NUMBER GIVEN IN THE EISSNER SINGLE
C           HEXADECIMAL CHARACTER FORM
C
C
C  INPUT :  (C*1)   CHR    = HEX. ORBITAL CHARACTER (EG. 'A')
C
C  OUTPUT:  (I*4)   I4NGRP = PRINCIPAL QUANTUM NUMBER FOR ORBITAL
C
C           (I*4)   I      = GENERAL INDEX
C
C  SUBROUTINES:  NONE
C  AUTHOR:  W.J. DICKSON, JET
C
C  DATE:    20/10/89
C
C  UPDATE:  19/02/03  H.P. SUMMERS - EXTENDED RANGE 
C
C UNIX-IDL PORT:
C
C VERSION: 1.1                          DATE: 22-1-96
C MODIFIED: TIM HAMMOND (TESSELLA SUPPORT SERVICES PLC)
C               - PUT UNDER SCCS CONTROL
C
C VERSION: 1.2                          DATE: 22-1-96
C MODIFIED: TIM HAMMOND (TESSELLA SUPPORT SERVICES PLC)
C               - PUT IN DEFAULT OF ZERO FOR RETURN VALUE.
C
C VERSION: 1.3                          DATE: 19-02-03
C MODIFIED: H.P. SUMMERS 
C		- EXTENDED RANGE 
C
C-----------------------------------------------------------------------
      CHARACTER           CHR