subroutine rdatax(itr,ic,iunit)
c     ===============================
c
c     for itr, itrx ne 0 - read input data for an individual transition
c     and prepare necessary auxiliary arrays
c
      INCLUDE 'IMPLIC.FOR'
      INCLUDE 'BASICS.FOR'
      INCLUDE 'ATOMIC.FOR'
      INCLUDE 'MODELQ.FOR'
c
      parameter (mtrx=1000)
      dimension iex(mtrx),itrind(mtrx),izx0(mtrx),izx1(mtrx),
     *          nmaxx(mtrx),izx(mtrx),nshx(mtrx),nax(mtrx),icx(mtrx),
     *          etx(mtrx),ssx(mtrx),dx(mtrx),
     *          aphx(11,5,mtrx),bphx(5,mtrx),a(11,5),b(5)
c
      if(itr.gt.0) then
         itrx=itrx+1
         ntrx=itrx
         ii=ilow(itr)
         ie=iel(ii)
         jj=iup(itr)
         iex(itrx)=ie
         icx(itrx)=ic
         itrind(itrx)=itr
         izx0(itrx)=iz(ie)
         izx1(itrx)=jj-1000
c
c        read inner-shell photoionization data from Omer's tables
c
         read(iunit,*) etx(itrx)
         read(iunit,*) nmaxx(itrx),izx(itrx),nshx(itrx)
         read(iunit,*) ssx(itrx)
         read(iunit,*) nax(itrx)
         read(iunit,*) dx(itrx)
         do i=1,nax(itrx)
            read(iunit,*) bphx(i,itrx)
         end do
         do j=1,nax(itrx)
            do i=1,11
               read(iunit,*) aphx(i,j,itrx)
            end do
         end do
       else if(itr.eq.0) then
c
c      for itr=0 - set up array BFCS with actual cross-sections
c
         if(ntrx.gt.0) then
            do itx=1,ntrx
               ie=iex(itx)
               it=itrind(itx)
               ii=ilow(it)
               ia=iatm(ii)
               iz1=izx1(itx)
               ic=icx(itx)
               jj=0
               do i=1,nlevel
                  if(iatm(i).eq.ia) then
                     if(iz(iel(i)).eq.iz1) then
                        jj=i
                        go to 10
                     end if
                  end if
               end do
   10          continue
               if(jj.eq.0) then
                  if(iz1.eq.iz(iel(nka(ia)-1))+1) jj=nka(ia)
               end if
               if(jj.eq.0) indexp(it)=0
c
               if(indexp(it).ne.0) then
                  iup(it)=jj
                  fr0(it)=etx(itx)/4.1357e-15
                  line(it)=.false.
                  itrcon(it)=ic
                  if(icol(it).ne.99) then
                     itra(ii,jj)=it
                     itra(jj,ii)=ic
                  end if
c  
                  write(6,601) itx,it,ii,jj,ia,
     *                         itra(ii,jj),itra(jj,ii),
     *                         icol(it),fr0(it),etx(itx)
  601             format(8i4,1pe12.4,0pf10.2)
               end if
            end do
         end if
c
       else
         nfreqb=nfreq
         if(ibfint.gt.0) nfreqb=nfreqc
         if(ntrx.gt.0) then
            do itx=1,ntrx
               it=itrind(itx)
               ic=icx(itx)
               if(indexp(it).ne.0) then
                  na=nax(itx)
                  do i=1,na
                     b(i)=bphx(i,itx)
                  end do
                  do j=1,na
                     do i=1,11
                        a(i,j)=aphx(i,j,itx)
                     end do
                  end do
c         
                  do ij=1,nfreqb
                     call bkhsgo(freq(ij),etx(itx),dx(itx),b,na,a,
     *               ssx(itx),nmaxx(itx),izx(itx),nshx(itx),sg)
                     bfcs(ic,ij)=real(sg)
                  end do
                  write(97,681) it,ic,ilow(it),iup(it),bfcs(ic,1)
  681             format(4i5,1p1e15.5)
               end if
            end do
         end if
      end if
      return
      end