subroutine quasim(ij)
c     =====================
c
c     quasi-molecular opacity for Lyman alpha, beta, gamma
c
      INCLUDE 'IMPLIC.FOR'
      INCLUDE 'BASICS.FOR'
      INCLUDE 'ATOMIC.FOR'
      INCLUDE 'MODELQ.FOR'
      common/quasun/tqmprf,iquasi,nunalp,nunbet,nungam,nunbal
      dimension sgd(mdepth)
c
      if(iquasi.le.0) return
      fr=freq(ij)
      wlam=2.997925e18/fr
      if(wlam.lt.911..or.wlam.gt.1727.) return
      ii=nfirst(ielh)
c
      do jup=2,iquasi+1
         jj=ii+1
         itr=itra(ii,jj)
         do id=1,nd
            anp=popul(nnext(ielh),id)
            t=temp(id)
            if(tqmprf.gt.0.) t=tqmprf
            call allard(wlam,t,popul(ii,id),anp,sg,1,jup)
            sgd(id)=sg
         end do
         if(ijlin(ij).ne.itr) then
            sg0=0.
            do ilint=1,nlines(ij)
               itt=itrlin(ilint,ij)
               if(itt.eq.itr) then
                  IJ0=IFR0(ITR)
                  DO IJT=IJ0,IFR1(ITR)
                     IF(FREQ(IJT).LE.FR) THEN
                     IJ0=IJT
                     GO TO 20
                     END IF
                  END DO
   20             IJ1=IJ0-1
                  A1=(FR-FREQ(IJ0))/(FREQ(IJ1)-FREQ(IJ0))
                  A2=UN-A1
                  do id=1,nd
                     SG0=A1*PRFLIN(ID,IJ1)+A2*PRFLIN(ID,IJ0)
                 end do
               end if
            end do
         end if
         do id=1,nd
            abso1(id)=abso1(id)+sgd(id)*abtra(itr,id)
            emis1(id)=emis1(id)+sgd(id)*emtra(itr,id)
         end do
      end do
c
      return
      end