ADAS Subroutine sigmin

      SUBROUTINE SIGMIN
      
      IMPLICIT REAL*8 (A-H,O-Z)
C-----------------------------------------------------------------------
C  PURPOSE: Calculates rate coefficients for excitation by ion impact
C-----------------------------------------------------------------------
C
C ADAS305 version. Developed from JETSHP.STARK.FORT (H P Summers).
C
C VERSION  : 1.1
C DATE     : 24-02-2005
C MODIFIED : Martin O'Mullane
C             - First version.
C
C VERSION  : 1.2
C DATE     : 16-05-2007
C MODIFIED : Allan Whiteford
C             - Updated comments as part of subroutine documentation
C               procedure.
C
C----------------------------------------------------------------------