prt_lines_hydro.cpp

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/* This file is part of Cloudy and is copyright (C)1978-2017 by Gary J. Ferland and
 * others.  For conditions of distribution and use see copyright notice in license.txt */
/*lines_hydro put H-like iso sequence into line intensity stack */
#include "cddefines.h"
#include "atmdat.h"
#include "dense.h"
#include "prt.h"
#include "hydrogenic.h"
#include "iso.h"
#include "rfield.h"
#include "geometry.h"
#include "lines.h"
#include "phycon.h"
#include "radius.h"
#include "secondaries.h"
#include "trace.h"
#include "two_photon.h"
#include "lines_service.h"
#include "elementnames.h"

static bool isSkipTransSet = false;
static vector< vector< pair<long, long> > > skipTrans( LIMELM );

/* This loop is identical to the one in lines_hydro() that brings together
 * the Balmer series, and resets all but one of the fine structure lines
 * to a zero intensity. */
static void collectSkipTrans( void )
{
        long ipISO = ipH_LIKE;

        for( long nelem=0; nelem < LIMELM; nelem++ )
        {
                if( dense.IonHigh[nelem] == nelem + 1 )
                {
                        vector< pair<long, long> > thisElm_skipTrans;

                        /* bring nL - n'L' emission together as n-n' emission. */
                        for( long ipHi=1; ipHi < iso_sp[ipH_LIKE][nelem].numLevels_max; ipHi++ )
                        {
                                long index_of_nHi_P;

                                /* is ipHi is collapsed level, index_of_nHi_P is ipHi */
                                if( N_(ipHi) > iso_sp[ipH_LIKE][nelem].n_HighestResolved_max )
                                        index_of_nHi_P = ipHi;
                                else
                                        index_of_nHi_P = iso_sp[ipH_LIKE][nelem].QuantumNumbers2Index[ N_(ipHi) ][1][2];

                                /* only need to consider resolved lower level here */
                                for( long ipLo=0; ipLo < ipHi; ipLo++ )
                                {       
                                        long index_of_nLo_S = iso_sp[ipH_LIKE][nelem].QuantumNumbers2Index[ N_(ipLo) ][0][2];

                                        /* jump out if ipLo is collapsed 
                                         * NB this must be up to n_HighestResolved_local and not n_HighestResolved_max */
                                        if( N_(ipLo) > iso_sp[ipH_LIKE][nelem].n_HighestResolved_local || N_(ipLo) == N_(ipHi) )
                                                break;

                                        if( iso_sp[ipH_LIKE][nelem].trans(ipHi,ipLo).Emis().Aul() <= iso_ctrl.SmallA )
                                                continue;

                                        /* add everything into nP - n'S, skip if current indices are those levels. */
                                        if( ipHi == index_of_nHi_P && ipLo == index_of_nLo_S )
                                                continue;
                                        else
                                        {
                                                thisElm_skipTrans.push_back( pair<long, long>( ipLo, ipHi ) );
                                                if( 0 )
                                                {
                                                        fprintf( ioQQQ,
                                                                "%2s\t index_of_nHi_P= %2ld (%5s)\t index_of_nLo_S= %2ld (%5s)\t"
                                                                " ipHi= %2ld (%5s)\t ipLo= %2ld (%5s)\t %10g %10g\t Dwl= %g\n",
                                                                elementnames.chElementSym[ nelem ],
                                                                index_of_nHi_P,
                                                                iso_sp[ipISO][nelem].st[index_of_nHi_P].chConfig().c_str(),
                                                                index_of_nLo_S,
                                                                iso_sp[ipISO][nelem].st[index_of_nLo_S].chConfig().c_str(),
                                                                ipHi,
                                                                iso_sp[ipISO][nelem].st[ipHi].chConfig().c_str(),
                                                                ipLo,
                                                                iso_sp[ipISO][nelem].st[ipLo].chConfig().c_str(),
                                                                iso_sp[ipISO][nelem].trans(index_of_nHi_P,index_of_nLo_S).WLAng(),
                                                                iso_sp[ipISO][nelem].trans(ipHi,ipLo).WLAng(),
                                                                iso_sp[ipISO][nelem].trans(index_of_nHi_P,index_of_nLo_S).WLAng() -
                                                                iso_sp[ipISO][nelem].trans(ipHi,ipLo).WLAng() );
                                                }
                                        }
                                }
                        }
                        skipTrans[ nelem ] = thisElm_skipTrans;
                }
        }

        isSkipTransSet = true;
}

static long this_ipLo, this_ipHi;
static bool isSkipped( const pair< long, long > level_indices )
{
        return level_indices.first == this_ipLo &&
                level_indices.second == this_ipHi;
}

static bool isTransSkipped( long nelem, long ipLo, long ipHi )
{
        this_ipLo = ipLo;
        this_ipHi = ipHi;

        vector< pair<long, long> >::iterator sti;
        sti = find_if( skipTrans[ nelem ].begin(), skipTrans[ nelem ].end(), isSkipped );

        bool skippedTrans = true;
        if( sti == skipTrans[ nelem ].end() )
                skippedTrans = false;
        return skippedTrans;
}

string iso_comment_tran_levels( long ipISO, long nelem, long ipLo, long ipHi )
{
        string isoSeq = "H-like, ";
        if( ipISO == ipHE_LIKE )
                isoSeq = "He-like, ";

        return isoSeq + db_comment_tran_levels( ipLo+1, ipHi+1 ) + ", "
                + GenerateTransitionConfiguration( iso_sp[ipISO][nelem].trans(ipHi,ipLo) );
}

void lines_hydro(void)
{
        long ipISO = ipH_LIKE;
        long int i, nelem, ipHi, ipLo;
        string chLabel="    ";

        double hbetab, 
                em , 
                caseb;

        DEBUG_ENTRY( "lines_hydro()" );

        if( trace.lgTrace )
                fprintf( ioQQQ, "   lines_hydro called\n" );

        // this can be changed with the atom levels command but must be at least 3
        ASSERT( iso_sp[ipH_LIKE][ipHYDROGEN].n_HighestResolved_max >= 3 );
        ASSERT( iso_sp[ipH_LIKE][ipHELIUM].n_HighestResolved_max >= 3 );

        i = StuffComment( "H-like iso-sequence" );
        linadd( 0., (realnum)i , "####", 'i',
                " start H -like iso sequence ");

        /*fprintf(ioQQQ," debugg\t%.2e\t%.2e\t%.2e\n", 
                radius.drad,
                iso_sp[ipH_LIKE][ipHYDROGEN].xLineTotCool , 
                iso_sp[ipH_LIKE][ipHYDROGEN].cLya_cool);*/

        /* >>chng 95 jun 25 changed from info to cooling to pick this up in primal.in   */
        linadd(MAX2(0.,iso_sp[ipH_LIKE][ipHYDROGEN].cLya_cool),1215.68,"Cool",'i',
                "collisionally excited La cooling ");

        linadd(MAX2(0.,-iso_sp[ipH_LIKE][ipHYDROGEN].cLya_cool),1215.68,"Heat",'i',
                "  collisionally de-excited La heating ");

        linadd(MAX2(0.,iso_sp[ipH_LIKE][ipHYDROGEN].cLyrest_cool),960,"Crst",'i',
                "  cooling due to n>2 Lyman lines ");

        linadd(MAX2(0.,-iso_sp[ipH_LIKE][ipHYDROGEN].cLyrest_cool),960,"Hrst",'i',
                "  heating due to n>2 Lyman lines ");

        linadd(MAX2(0.,iso_sp[ipH_LIKE][ipHYDROGEN].cBal_cool),4861.36,"Crst",'i',
                "  cooling due to n>3 Balmer lines ");

        linadd(MAX2(0.,-iso_sp[ipH_LIKE][ipHYDROGEN].cBal_cool),4861.36,"Hrst",'i',
                "  heating due to n>3 Balmer lines ");

        linadd(MAX2(0.,iso_sp[ipH_LIKE][ipHYDROGEN].cRest_cool),0,"Crst",'i',
                "  cooling due to higher Paschen lines ");

        linadd(MAX2(0.,-iso_sp[ipH_LIKE][ipHYDROGEN].cRest_cool),0,"Hrst",'i',
                "  heating due to higher Paschen lines ");

        /* remember largest fractional ionization of H due to secondaries */
        secondaries.SecHIonMax = MAX2( secondaries.SecHIonMax , secondaries.sec2total );

        /* remember fraction of H ionizations due to ct */
        atmdat.HIonFracMax = MAX2( atmdat.HIonFracMax, atmdat.HIonFrac);

        /* remember largest fraction of thermal collisional ionization of H ground state */
        hydro.HCollIonMax = 
                (realnum)MAX2( hydro.HCollIonMax , hydro.H_ion_frac_collis );

        linadd(secondaries.x12tot*iso_sp[ipH_LIKE][ipHYDROGEN].st[ipH1s].Pop()*1.634e-11,1215.68,"LA X" ,'i',
                "Lya contribution from suprathermal secondaries from ground ");

        linadd(MAX2(0.,iso_sp[ipH_LIKE][ipHYDROGEN].coll_ion),0,"CION",'c',
                "collision ionization cooling of hydrogen ");

        linadd(MAX2(-iso_sp[ipH_LIKE][ipHYDROGEN].coll_ion,0.),0,"3bHt",'h',
                "  this is the heating due to 3-body recombination ");

        linadd(MAX2(0.,iso_sp[ipH_LIKE][ipHELIUM].coll_ion),0,"He2C",'c',
                "collision ionization cooling of He+ ");

        linadd(MAX2(-iso_sp[ipH_LIKE][ipHELIUM].coll_ion,0.),0,"He2H",'h',
                "  this is the heating due to 3-body recombination onto He+");

        fixit("why is there a zero here?");
        linadd(iso_sp[ipH_LIKE][ipHYDROGEN].st[ipH2p].Pop()*0.*iso_sp[ipH_LIKE][ipHYDROGEN].ex[ipH2p][ipH1s].pestrk*1.634e-11,1215.68,"Strk",'i',
          "  Stark broadening contribution to line ");

        linadd(iso_sp[ipH_LIKE][ipHYDROGEN].st[ipH3s].Pop()*iso_sp[ipH_LIKE][ipHYDROGEN].ex[ipH3s][ipH2p].pestrk*3.025e-12,
          6562.85,"Strk",'i',
          "  Stark broadening contribution to line ");

        linadd(iso_sp[ipH_LIKE][ipHYDROGEN].st[ipH4s].Pop()*iso_sp[ipH_LIKE][ipHYDROGEN].ex[ipH4s][ipH2p].pestrk*4.084e-12,
          4861.36,"Strk",'i',
          "Stark broadening contribution to line ");

        linadd(iso_sp[ipH_LIKE][ipHYDROGEN].st[ipH4p].Pop()*iso_sp[ipH_LIKE][ipHYDROGEN].ex[ipH4p][ipH3s].pestrk*1.059e-12,
          18751,"Strk",'i',
                   " Stark broadening contribution to line ");

        /* pestrk[5,4] is A[4,5]*pest[4,5] 
         * Stark broadening contribution to line */
        if( iso_sp[ipH_LIKE][ipHYDROGEN].n_HighestResolved_max >= 5 )
        {
                long ip5p = iso_sp[ipH_LIKE][ipHYDROGEN].QuantumNumbers2Index[5][1][2];
                linadd(iso_sp[ipH_LIKE][ipHYDROGEN].st[ip5p].Pop()*iso_sp[ipH_LIKE][ipHYDROGEN].ex[ip5p][ipH4s].pestrk*4.900e-13,40512,"Strk",'i',
                        "Stark broadening part of line");
        }
        /* this can fail if RT_line_all never updates the ots rates, a logic error,
         * but only assert this during actual calculation (ipass>0), */
        ASSERT( LineSave.ipass  <1 ||
                iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH2p,ipH1s).Emis().ots()>= 0.);

        linadd(iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH2p,ipH1s).Emis().ots()*iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH2p,ipH1s).EnergyErg(), 1215.68,"Dest",'i',
                "  portion of line lost due to absorp by background opacity ");

        /* portion of line lost due to absorb by background opacity */
        linadd(iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH3p,ipH2s).Emis().ots()*iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH3p,ipH2s).EnergyErg(), 6562.85,"Dest",'i',
                "Ha destroyed by background opacity");

        /* portion of line lost due to absorp by background opacity */
        if( iso_sp[ipH_LIKE][ipHYDROGEN].n_HighestResolved_max >= 5 )
        {
                long ip5p = iso_sp[ipH_LIKE][ipHYDROGEN].QuantumNumbers2Index[5][1][2];
                linadd(iso_sp[ipH_LIKE][ipHYDROGEN].trans(ip5p,ipH4s).Emis().ots()*iso_sp[ipH_LIKE][ipHYDROGEN].trans(ip5p,ipH4s).EnergyErg(),40516, "Dest",'i',
                        "portion of line lost due to absorb by background opacity");
        }

        /* portion of line lost due to absorb by background opacity */
        if( iso_sp[ipH_LIKE][ipHYDROGEN].numLevels_max > ipH4p )
                linadd(iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH4p,ipH2s).Emis().ots()*iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH4p,ipH2s).EnergyErg(), 4861.36,"Dest",'i',
                        "portion of line lost due to absorb by background opacity");

        /* portion of line lost due to absorb by background opacity */
        if( iso_sp[ipH_LIKE][ipHYDROGEN].numLevels_max > ipH4p )
                linadd(iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH4p,ipH3s).Emis().ots()*iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH4p,ipH3s).EnergyErg() ,18751, "Dest",'i',
                        "portion of line lost due to absorb by background opacity");

        linadd(iso_sp[ipH_LIKE][ipHYDROGEN].st[ipH2p].Pop()*iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH2p,ipH1s).Emis().Aul()*
                hydro.dstfe2lya*iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH2p,ipH1s).EnergyErg() , 1215.68 , "Fe 2" , 'i',
                "Ly-alpha destroyed by overlap with FeII " );

        linadd(iso_sp[ipH_LIKE][ipHYDROGEN].RadRec_caseB*dense.xIonDense[ipHYDROGEN][1]*dense.eden * 1.64e-11,1215.68,"Ca B",'i',
                " simple high-density case b intensity of Ly-alpha, no two photon ");

        /* these entries only work correctly if the APERTURE command is not in effect */
        if( geometry.iEmissPower == 2 )
        {
                /* H-beta computed from Q(H) and specified covering factor */
                if( nzone == 1 )
                {
                        /* evaluate the case b emissivity by interpolating on the hummer & storey tables */
                        caseb = rfield.qhtot*
                                atmdat_HS_caseB( 4 , 2 , 1 , phycon.te , dense.eden, 'b' ) / iso_sp[ipH_LIKE][ipHYDROGEN].RadRec_caseB;
                        /* the atmdat_HS_caseB returned -1 if the physical conditions were outside range of validity.  
                         * In this case use simple approximation with no temperature or density dependence */
                        if( caseb < 0 )
                        {
                                caseb = rfield.qhtot*4.75e-13;
                        }
                        LineSave.lines[LineSave.nsum].SumLineZero();
                }
                else
                {
                        caseb = 0.;
                }
                /* H-beta computed from Q(H) and specified covering factor */
                linadd( caseb/radius.dVeffAper*geometry.covgeo , 4861.36 , "Q(H)" , 'i' ,
                        "Case B H-beta computed from Q(H) and specified covering factor");

                if( nzone == 1 )
                {
                        // the cast to double prevents an FPE with Solaris Studio 12.4 (limit_compton_hi_t.in)
                        caseb = rfield.qhtot*double(iso_sp[ipH_LIKE][ipHYDROGEN].trans(ipH2p,ipH1s).EnergyErg());
                        LineSave.lines[LineSave.nsum].SumLineZero();
                }
                else
                {
                        caseb = 0.;
                }
                /* >>chng 02 nov 05, better approximation for Lya for temperature of first zone */
                linadd( caseb/radius.dVeffAper*geometry.covgeo , 1215.68 , "Q(H)" , 'i',
                        "Ly-alpha from Q(H), high-dens lim, specified covering factor" );
        }

        /* this is the main printout, where line intensities are entered into the stack */
        for( nelem=ipISO; nelem < LIMELM; nelem++ )
        {
                if( dense.lgElmtOn[nelem] )
                {
                        ASSERT( iso_sp[ipH_LIKE][nelem].n_HighestResolved_max >= 3 );

                        for( ipHi=1; ipHi < iso_sp[ipISO][nelem].numLevels_max; ipHi++ )
                        {
                                for( ipLo=0; ipLo < ipHi; ipLo++ )
                                {
                                        if( iso_sp[ipISO][nelem].trans(ipHi,ipLo).Emis().Aul() <= iso_ctrl.SmallA )
                                                continue;

                                        set_xIntensity( iso_sp[ipISO][nelem].trans(ipHi,ipLo) );
                                }
                        }
                }
        }

        if( ! isSkipTransSet )
        {
                collectSkipTrans();
        }

        /* create emissivity or intensity for hydrogenic species,
         * first combine/bring balmer series together */
        for( nelem=0; nelem < LIMELM; nelem++ )
        {
                if( dense.IonHigh[nelem] == nelem + 1 )
                {
                        /* bring nL - n'L' emission together as n-n' emission. */
                        for( ipHi=1; ipHi < iso_sp[ipH_LIKE][nelem].numLevels_max; ipHi++ )
                        {
                                long index_of_nHi_P;

                                /* is ipHi is collapsed level, index_of_nHi_P is ipHi */
                                if( N_(ipHi) > iso_sp[ipH_LIKE][nelem].n_HighestResolved_max )
                                        index_of_nHi_P = ipHi;
                                else
                                        index_of_nHi_P = iso_sp[ipH_LIKE][nelem].QuantumNumbers2Index[ N_(ipHi) ][1][2];

                                /* only need to consider resolved lower level here */
                                for( ipLo=0; ipLo < ipHi; ipLo++ )
                                {       
                                        long index_of_nLo_S = iso_sp[ipH_LIKE][nelem].QuantumNumbers2Index[ N_(ipLo) ][0][2];

                                        /* jump out if ipLo is collapsed 
                                         * NB this must be up to n_HighestResolved_local and not n_HighestResolved_max */
                                        if( N_(ipLo) > iso_sp[ipH_LIKE][nelem].n_HighestResolved_local || N_(ipLo) == N_(ipHi) )
                                                break;

                                        if( iso_sp[ipH_LIKE][nelem].trans(ipHi,ipLo).Emis().Aul() <= iso_ctrl.SmallA )
                                                continue;

                                        /* add everything into nP - n'S, skip if current indices are those levels. */
                                        if( ipHi == index_of_nHi_P && ipLo == index_of_nLo_S )
                                                continue;
                                        else
                                        {
                                                /* add resolved line to nP - n'S */
                                                iso_sp[ipH_LIKE][nelem].trans(index_of_nHi_P,index_of_nLo_S).Emis().xIntensity() +=
                                                        iso_sp[ipH_LIKE][nelem].trans(ipHi,ipLo).Emis().xIntensity();
                                                iso_sp[ipH_LIKE][nelem].trans(index_of_nHi_P,index_of_nLo_S).Emis().xObsIntensity() +=
                                                        iso_sp[ipH_LIKE][nelem].trans(ipHi,ipLo).Emis().xObsIntensity();
                                                /* zero out the resolved line */
                                                iso_sp[ipH_LIKE][nelem].trans(ipHi,ipLo).Emis().xIntensity() = 0;
                                                iso_sp[ipH_LIKE][nelem].trans(ipHi,ipLo).Emis().xObsIntensity() = 0;
                                                //ASSERT( iso_sp[ipH_LIKE][nelem].trans(index_of_nHi_P,index_of_nLo_S).Emis().xIntensity() >= 0. );
                                                //ASSERT( iso_sp[ipH_LIKE][nelem].trans(index_of_nHi_P,index_of_nLo_S).Emis().xObsIntensity() >= 0. );
                                        }
                                }
                        }
                }
        }

        /* H beta recombination, assuming old case B */
        hbetab = (double)((exp10(-20.89 - 0.10612*POW2(phycon.alogte - 4.4)))/
          phycon.te);
        /* need to pass this assert if CaBo is to have valid array indices for ipCont */
        /* 06 aug 28, from numLevels_max to _local. */
        /* 06 dec 21, change from numLevels_max to _local was mistake for this entire file.  Undo. */
        ASSERT( iso_sp[ipH_LIKE][ipHYDROGEN].numLevels_max > 4 );
        hbetab *= dense.xIonDense[ipHYDROGEN][1]*dense.eden;

        lindst(hbetab, -4861.36 ,"CaBo",
                1 ,'i',false,
                " this is old case b based on Ferland (1980) PASP ");

        if( dense.lgElmtOn[ipHELIUM] )
        {
                /* need to pass this assert if CaBo is to have valid array indices for ipCont */
                /* 06 aug 28, from numLevels_max to _local. */
                /* 06 dec 21, change from numLevels_max to _local was mistake for this entire file.  Undo. */
                ASSERT( iso_sp[ipH_LIKE][ipHELIUM].numLevels_max > 4 );
                /* 1640 1640 1640 */
                em = 2.03e-20/(phycon.te70*phycon.te10*phycon.te03);
                em *= dense.xIonDense[ipHELIUM][2]*dense.eden;

                lindst(em,-1640,"CaBo",
                        1,'i',false,
                        " old prediction of He II 1640, Case B at low densities");

                /* hydrogenic helium */
                /* old prediction of He II 4686, case B */
                em = 2.52e-20/(pow(phycon.te,1.05881));
                em *= dense.xIonDense[ipHELIUM][2]*dense.eden;

                lindst(em,-4686.01,"CaBo",      1,'i',false,
                           " old prediction of He II 4686, Case B at low densities");
        }

        /* predict case b intensities of hydrogen lines */
        if( LineSave.ipass <= 0 )
        {
                for(nelem=0; nelem<HS_NZ; ++nelem )
                {
                        atmdat.lgHCaseBOK[0][nelem] = true;
                        atmdat.lgHCaseBOK[1][nelem] = true;
                }
        }
        /* this is the main printout, where line intensities are entered into the stack */
        for( nelem=0; nelem < LIMELM; nelem++ )
        {
                if( dense.lgElmtOn[nelem] )
                {
                        /* HS_NZ is limit to charge of elements in HS predictions, now 8 == oxygen */
                        /* but don't do the minor elements, Li, Be, B - these were not read in and so should not be
                         * printed - remove equivalent if statement in atmdat_readin.cpp to read them in */
                        if( nelem < HS_NZ && (nelem<2 || nelem>4) )
                        {
                                int iCase;
                                for( iCase=0; iCase<2; ++iCase )
                                {
                                        char chAB[2]={'A','B'};
                                        char chLab[5]="Ca  ";

                                        /* adding iCase means start from n=1 for case A, n=2 for Case B,
                                         * note that principal quantum number is on physics scale, not C */
                                        /* 06 aug 28, both of these from numLevels_max to _local. */
                                        /* 06 dec 21, change from numLevels_max to _local was mistake for this entire file.  Undo. */
                                        /* HS data file extends to ipHi == atmdat.ncut[iCase][nelem]==25, report all possible values for comparisons */
                                        for( ipLo=1+iCase; ipLo<MIN2(atmdat.ncut[iCase][nelem]-1,iso_sp[ipH_LIKE][nelem].n_HighestResolved_max + iso_sp[ipH_LIKE][nelem].nCollapsed_max); ++ipLo )
                                        {
                                                for( ipHi=ipLo+1; ipHi< MIN2(atmdat.ncut[iCase][nelem],iso_sp[ipH_LIKE][nelem].n_HighestResolved_max + iso_sp[ipH_LIKE][nelem].nCollapsed_max+1); ++ipHi )
                                                {
                                                        realnum wl;
                                                        double case_b_Intensity;
                                                        long int ipCHi , ipCLo;
                                                        /* Put case b predictions into line stack
                                                         * NB NB NB each Hummer & Storey case b line must be 
                                                         * explicitly clobbered by hand in routine final if 
                                                         * atmdat.lgHCaseBOK[iCase][nelem] flag is set false
                                                         * since this indicates that we exceeded bounds of table,
                                                         * DO NOT want to print lines in that case */

                                                        /* first do case b emissivity of balmer lines */

                                                        /* get HS predictions */
                                                        case_b_Intensity = atmdat_HS_caseB( ipHi,ipLo , nelem+1, phycon.te , dense.eden, chAB[iCase] );
                                                        if( case_b_Intensity<=0. )
                                                        {
                                                                atmdat.lgHCaseBOK[iCase][nelem] = false;
                                                                case_b_Intensity = 0.;
                                                        }

                                                        case_b_Intensity *= dense.xIonDense[nelem][nelem+1-ipISO]*dense.eden;

                                                        if( iCase==0 && ipLo==1 )
                                                        {
                                                                /* get physical scal prin quant numbers onto cloudy c scale */
                                                                ipCHi = ipHi;
                                                                ipCLo = 0;
                                                        }
                                                        else
                                                        {
                                                                /* get physical scal prin quant numbers onto cloudy c scale */
                                                                ipCHi = ipHi;
                                                                ipCLo = ipLo;
                                                        }

                                                        /* make label either Ca A or Ca B */
                                                        chLab[3] = chAB[iCase];

                                                        /* new treatment is different from old for indices greater than 2. */
                                                        if( ipCHi > 2 )
                                                        {
                                                                if( ipCLo >  2 )
                                                                {
                                                                        /* if both indices above two, just treat as nP to n'S transition. */
                                                                        ipCHi = iso_sp[ipH_LIKE][nelem].QuantumNumbers2Index[ipCHi][1][2];
                                                                        ipCLo = iso_sp[ipH_LIKE][nelem].QuantumNumbers2Index[ipCLo][0][2];
                                                                }
                                                                else if(  ipCLo ==  2 )
                                                                {
                                                                        /* treat as nS to 2P transition. */
                                                                        ipCHi = iso_sp[ipH_LIKE][nelem].QuantumNumbers2Index[ipCHi][0][2];
                                                                }
                                                                else if( ipCLo ==  1 || ipCLo == 0 )
                                                                {
                                                                        /* treat as nP to n'S transition. */
                                                                        ipCHi = iso_sp[ipH_LIKE][nelem].QuantumNumbers2Index[ipCHi][1][2];
                                                                }
                                                        }

                                                        /* this is wavelength of interpolated case b from HS tables */
                                                        wl = iso_sp[ipH_LIKE][nelem].trans(ipCHi,ipCLo).WLAng();
                                                        atmdat.WaveLengthCaseB[nelem][ipHi][ipLo] = wl;

                                                        lindst(case_b_Intensity,wl,chLab,iso_sp[ipH_LIKE][nelem].trans(ipCHi,ipCLo).ipCont(),'i',false,
                                                                " case a or case b from Hummer & Storey tables" );
                                                }
                                        }
                                }
                        }

                        // add two-photon details here
                        if( LineSave.ipass == 0 )
                        {
                                /* chIonLbl is function that generates a null terminated 4 char string, of form "C  2" 
                                 * the result, chLable, is only used when ipass == 0, can be undefined otherwise */
                                chLabel = chIonLbl(nelem+1, nelem+1-ipISO);
                        }
                        for( vector<two_photon>::iterator tnu = iso_sp[ipH_LIKE][nelem].TwoNu.begin(); tnu != iso_sp[ipH_LIKE][nelem].TwoNu.end(); ++tnu )
                        {
                                fixit("This was multiplied by Pesc when treated as a line, now what?  Only used for printout?");
                                fixit("below should be 'i' instead of 'r' ?");

                                string tpc_comment = "",
                                        tpe_comment = "";
                                if( LineSave.ipass == 0 )
                                {
                                        string comment_trans = iso_comment_tran_levels( ipISO, nelem, ipH1s, ipH2s );
                                        tpc_comment = " two photon continuum, " + comment_trans;
                                        tpe_comment = " induced two photon emission, " + comment_trans;
                                }
                                linadd( tnu->AulTotal * tnu->E2nu * EN1RYD * (*tnu->Pop), 
                                         0, chLabel.c_str(), 'r', tpc_comment.c_str() );

                                linadd( tnu->induc_dn * tnu->E2nu * EN1RYD * (*tnu->Pop), 
                                        22, chLabel.c_str() ,'i', tpe_comment.c_str() );
                        }

                        /* NB NB - low and high must be in this order so that all balmer, paschen,
                         * etc series line up correctly in final printout */
                        for( ipLo=ipH1s; ipLo < iso_sp[ipH_LIKE][nelem].numLevels_max-1; ipLo++ )
                        {
                                /* don't bother with decays to 2p since we set them to zero above */
                                if( ipLo==ipH2p )
                                        continue;

                                /* set number of levels we want to print, first is default,
                                 * only print real levels, second is set with "print line
                                 * iso collapsed" command */
                                long int nLoop  = iso_sp[ipH_LIKE][nelem].numLevels_max - iso_sp[ipH_LIKE][nelem].nCollapsed_max;
                                if( prt.lgPrnIsoCollapsed )
                                        nLoop  = iso_sp[ipH_LIKE][nelem].numLevels_max;

                                for( ipHi=ipLo+1; ipHi < nLoop; ipHi++ )
                                {
                                        // skip non-radiative transitions
                                        if( iso_sp[ipH_LIKE][nelem].trans(ipHi,ipLo).ipCont() < 1 )
                                                continue;

                                        // skip 2s-1s, so that 2p-1s comes first and cdLine finds LyA instead of the M2 transition.     
                                        if( ipHi==1 && ipLo==0 )
                                                continue;

                                        if( isTransSkipped( nelem, ipLo, ipHi ) )
                                                continue;

                                        string comment_trans = "";
                                        if( LineSave.ipass == 0 )
                                        {
                                                comment_trans = iso_comment_tran_levels( ipISO, nelem, ipLo, ipHi );
                                        }
                                        PutLine(iso_sp[ipH_LIKE][nelem].trans(ipHi,ipLo), comment_trans.c_str());
                                }
                        }
                }
        }
        
        if( trace.lgTrace )
        {
                fprintf( ioQQQ, "   lines_hydro returns\n" );
        }
        return;
}