FUNCTION CROSS(IBFT,IJ)
C     =======================
C
C     Evaluation of the photoionization cross-section 
C     IBF - index ot the b-f transition
C     IJ  - frequency index
C
      INCLUDE 'IMPLIC.FOR'
      INCLUDE 'BASICS.FOR'
      INCLUDE 'ATOMIC.FOR'
      INCLUDE 'MODELQ.FOR'
C
      IJ0=IJBF(IJ)
      A1=AIJBF(IJ)
      CROSS=A1*BFCS(IBFT,IJ0)+(UN-A1)*BFCS(IBFT,IJ0+1)
c
      RETURN
      END