mole_h2_etc.cpp

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/* This file is part of Cloudy and is copyright (C)1978-2013 by Gary J. Ferland and
 * others.  For conditions of distribution and use see copyright notice in license.txt */
/* mole_H2_LTE sets Boltzmann factors and LTE unit population of large H2 molecular */
/* H2_zero_pops_too_low - zero out some H2 variables if we decide not to compute
 * the full sim, called by H2_LevelPops*/
/* H2_Solomon_rate find rates between H2s and H2g and other levels,
 * for eventual use in the chemistry */
/* gs_rate evaluate rates between ground and star states */
/* H2_He_coll_init initialize H2 - He collision data set
 * H2_He_coll interpolate on h2 - He collision data set to return rate at temp*/
#include "cddefines.h" 
#include "phycon.h" 
#include "hmi.h" 
#include "taulines.h" 
#include "h2.h" 
#include "h2_priv.h" 
#include "rfield.h"
#include "thermal.h"
#include "gammas.h"
#include "ionbal.h"

/*H2_Solomon_rate find rates between H2s and H2g and other levels,
 * for eventual use in the chemistry */
void diatomics::H2_Solomon_rate( void )
{
        DEBUG_ENTRY( "H2_Solomon_rate()" );

        /* iElecLo will always be X in this routine */

        /* find rate (s-1) h2 dissociation into X continuum by Solomon process and
         * assign to the TH85 g and s states 
         * these will go back into the chemistry network */

        /* rates [s-1] for dissociation from s or g, into electronic excited states  
         * followed by dissociation */
        Solomon_dissoc_rate_g = 0.;
        Solomon_dissoc_rate_s = 0.;

        /* these are used in a print statement - are they needed? */
        Solomon_elec_decay_g = 0.;
        Solomon_elec_decay_s = 0.;

        /* at this point we have already evaluated the sum of the radiative rates out
         * of the electronic excited states - this is H2_rad_rate_out[electronic][vib][rot] 
         * and this includes both decays into the continuum and bound states of X */

        for( TransitionList::iterator tr = trans.begin(); tr != rad_end; ++tr )
        {
                qList::iterator Hi = (*tr).Hi() ;       
                if( (*Hi).n() < 1 ) continue;
                double factor = (double)H2_dissprob[(*Hi).n()][(*Hi).v()][(*Hi).J()]/H2_rad_rate_out[(*Hi).n()][(*Hi).v()][(*Hi).J()];
                /* this is the rate [cm-3 s-1] that mole goes from 
                 * lower level into electronic excited states then 
                 * into continuum */
                double rate_up_cont = (*(*tr).Lo()).Pop() * (*tr).Emis().pump() * factor;

                /* rate electronic state decays into H2g */
                double elec_decay = (*(*tr).Hi()).Pop() * (*tr).Emis().Aul() *
                        ((*tr).Emis().Pesc() + (*tr).Emis().Pdest() + (*tr).Emis().Pelec_esc());
                if( (*(*tr).Lo()).energy().WN() > ENERGY_H2_STAR && hmi.lgLeiden_Keep_ipMH2s )
                {
                        /* this is H2g up to excited then to continuum - 
                         * cm-3 s-1 at this point */
                        Solomon_dissoc_rate_s += rate_up_cont;
                        /* rate electronic state decays into H2g */
                        Solomon_elec_decay_s += elec_decay;
                }
                else
                {
                        /* this is H2g up to excited then to continuum - 
                         * cm-3 s-1 at this point */
                        Solomon_dissoc_rate_g += rate_up_cont;
                        /* rate electronic state decays into H2g */
                        Solomon_elec_decay_g += elec_decay;
                }
        }

        double H2_sum_excit_elec_den = GetExcitedElecDensity();

        /* at this point units of Solomon_elec_decay_g, H2s are cm-3 s-1 
         * since populations are included -
         * div by pops to get actual dissocation rate, s-1 */
        if( *dense_total > SMALLFLOAT )
        {
                Solomon_elec_decay_g /= SDIV( H2_sum_excit_elec_den );
                Solomon_elec_decay_s /= SDIV( H2_sum_excit_elec_den );

                /* will be used for H2s-> H + H */
                Solomon_dissoc_rate_s /= SDIV(H2_den_s);

                /* will be used for H2g-> H + H */
                Solomon_dissoc_rate_g /= SDIV(H2_den_g);

        }
        else
        {
                Solomon_dissoc_rate_s = 0.; 
                Solomon_dissoc_rate_g = 0.;     

        }
        /*fprintf(ioQQQ,"DEBUG H2 new %.2e %.2e %.2e %.2e \n",
                Solomon_elec_decay_g ,
                Solomon_elec_decay_s ,
                Solomon_dissoc_rate_s,
                Solomon_dissoc_rate_g );*/

        return;
}

/* gs_rate evaluate rate between ground and star states */
double diatomics::gs_rate( void )
{
        DEBUG_ENTRY( "diatomics::gs_rate()" );

        /* rate g goes to s */
        double ground_to_star_rate = 0.;

        /* loop over all levels in H2g */
        for( long ipLoX=0; ipLoX < nEner_H2_ground; ++ipLoX )
        {
                /* now find all pumps up to electronic excited states */
                /* sum over all electronic states, finding dissociation rate */
                for( long iElecHi=1; iElecHi<n_elec_states; ++iElecHi )
                {
                        for( long iVibHi=0; iVibHi<=nVib_hi[iElecHi]; ++iVibHi )
                        {
                                for( long iRotHi=Jlowest[iElecHi]; iRotHi<=nRot_hi[iElecHi][iVibHi]; ++iRotHi )
                                {
                                        long ipHi = ipEnergySort[iElecHi][iVibHi][iRotHi];
                                        if( lgH2_radiative[ipHi][ipLoX] )
                                        {
                                                /* this is the rate [cm-3 s-1] that mole goes from 
                                                 * lower level into electronic excited states then 
                                                 * into continuum */
                                                double rate_up_cont = 
                                                        states[ipLoX].Pop() *
                                                        trans[ ipTransitionSort[ipHi][ipLoX] ].Emis().pump();
                                                double decay_star = H2_rad_rate_out[iElecHi][iVibHi][iRotHi] - H2_dissprob[iElecHi][iVibHi][iRotHi];
                                                /* loop over all other levels in H2g, subtracting 
                                                 * their rate - remainder is rate into star, this is 
                                                 * usually only a few levels */
                                                for( long ipOther=0; ipOther < nEner_H2_ground; ++ipOther )
                                                {
                                                        if( lgH2_radiative[ipHi][ipOther] ) 
                                                        {
                                                                EmissionProxy em = trans[ ipTransitionSort[ipHi][ipOther] ].Emis();
                                                                decay_star -= em.Aul() * ( em.Pesc() + em.Pdest() + em.Pelec_esc() );
                                                        }
                                                }
                                                /* MAX because may underflow to negative numbers is rates very large 
                                                 * this is fraction that returns to H2s */
                                                decay_star = MAX2(0., decay_star)/SDIV(H2_rad_rate_out[iElecHi][iVibHi][iRotHi]);
                                                ground_to_star_rate += rate_up_cont*decay_star;

                                        }/* end if line exists */
                                }/* end loop rot electronic excited */
                        }/* end loop vib electronic excited */
                }/* end loop electronic electronic excited */
        }

        /* at this point units are cm-3 s-1 - convert to rate s-1 */
        ground_to_star_rate /= SDIV( H2_den_g );
        return ground_to_star_rate;
}

long diatomics::OpacityCreate( double *stack )
{
        DEBUG_ENTRY( "diatomics::OpacityCreate()" );

        ASSERT( photoion_opacity_fun != NULL );

        for( long i=ip_photo_opac_thresh-1; i < rfield.nupper; i++ )
        {
                /* >>chng 05 nov 24, add H2 photoionization cross section */
                //opac.OpacStack[i-ip_photo_opac_thresh + ip_photo_opac_offset] =
                stack[ i - ip_photo_opac_thresh + ip_photo_opac_offset ] =
                        photoion_opacity_fun( rfield.AnuOrg[i] );
                        //Yan_H2_CS(rfield.AnuOrg[i]);
        }
         
        //opac.nOpacTot += rfield.nupper - ip_photo_opac_thresh + 1;
        return rfield.nupper - ip_photo_opac_thresh + 1;
}

/* H2_zero_pops_too_low - zero out some H2 variables if we decide not to compute
 * the full sim, called by H2_LevelPops*/
void diatomics::H2_zero_pops_too_low( void )
{
        DEBUG_ENTRY( "H2_zero_pops_too_low()" );

        // zero populations
        fill_n( pops_per_elec, N_ELEC, 0. );
        pops_per_vib.zero();
        for( qList::iterator st = states.begin(); st != states.end(); ++st )
        {
                double pop = H2_populations_LTE[ (*st).n() ][ (*st).v() ][ (*st).J() ] * (*dense_total);
                H2_old_populations[ (*st).n() ][ (*st).v() ][ (*st).J() ] = pop;
                (*st).Pop() = pop;
        }


        for( TransitionList::iterator tr = trans.begin(); tr != rad_end; ++tr )
        {
                /* population of lower level with correction for stim emission */
                (*tr).Emis().PopOpc() = (*(*tr).Lo()).Pop() - (*(*tr).Hi()).Pop() * (*(*tr).Lo()).g() / (*(*tr).Hi()).g();
                                                                
                /* following two heat exchange excitation, deexcitation */
                (*tr).Coll().cool() = 0.;
                (*tr).Coll().heat() = 0.;

                /* intensity of line */
                (*tr).Emis().xIntensity() = 0.;
                (*tr).Emis().phots() = 0.;
                (*tr).Emis().ots() = 0.;
        }

        photodissoc_BigH2_H2s = 0.;
        photodissoc_BigH2_H2g = 0.;
        HeatDiss = 0.;
        HeatDexc = 0.;
        HeatDexc_deriv = 0.;
        Solomon_dissoc_rate_g = 0.;
        Solomon_dissoc_rate_s = 0.;
        return;
}

/*mole_H2_LTE sets Boltzmann factors and LTE unit population of large H2 molecular */
void diatomics::mole_H2_LTE( void )
{
        DEBUG_ENTRY( "mole_H2_LTE()" );

        /* do we need to update the Boltzmann factors and unit LTE populations? */
        if( ! fp_equal( phycon.te, TeUsedBoltz ) )
        {
                double part_fun = 0.;
                TeUsedBoltz = phycon.te;
                /* loop over all levels setting H2_Boltzmann and deriving partition function */
                for( qList::const_iterator st = states.begin(); st != states.end(); ++st )
                {
                        long iElec = (*st).n();
                        long iVib = (*st).v();
                        long iRot = (*st).J();
                        H2_Boltzmann[iElec][iVib][iRot] = 
                                /* energy is relative to lowest level in the molecule, v=0, J=0,
                                 * so Boltzmann factor is relative to this level */
                                sexp( (*st).energy().K() / phycon.te );
                        /* sum the partition function - Boltzmann factor times statistical weight */
                        part_fun += H2_Boltzmann[iElec][iVib][iRot] * (*st).g();
                        ASSERT( part_fun > 0 );
                }
                /* have partition function, set H2_populations_LTE (populations for unit H2 density) */
                for( qList::const_iterator st = states.begin(); st != states.end(); ++st )
                {
                        long iElec = (*st).n();
                        long iVib = (*st).v();
                        long iRot = (*st).J();
                        /* these are the H2 LTE populations for a unit H2 density -
                         * these populations will sum up to unity */
                        H2_populations_LTE[iElec][iVib][iRot] = 
                                H2_Boltzmann[iElec][iVib][iRot] * 
                                (*st).g() / part_fun;
                }
                if( nTRACE >= n_trace_full ) 
                        fprintf(ioQQQ,
                        "mole_H2_LTE set H2_Boltzmann factors, T=%.2f, partition function is %.2f\n",
                        phycon.te,
                        part_fun);
        }

        return;
}

/*H2_Reset called by IterRestart to reset variables that are needed after an iteration */
void diatomics::H2_Reset( void )
{

        DEBUG_ENTRY( "H2_Reset()" );

        if(nTRACE) 
                fprintf(ioQQQ,
                "\n***************H2_Reset called, resetting nCall_this_iteration, zone %.2f iteration %li\n", 
                fnzone,
                iteration );

        /* number of times large molecules evaluated in this iteration,
         * is false if never evaluated, on next evaluation will start with LTE populations */
        nCall_this_iteration = 0;

        /* these remember the largest and smallest factors needed to
         * renormalize the H2 chemistry */
        renorm_max = 1.;
        renorm_min = 1.;

        /* counters used by H2_itrzn to find number of calls of h2 per zone */
        nH2_pops = 0;
        nH2_zone = 0;
        /* this is used to establish zone number for evaluation of number of levels in matrix */
        nzone_nlevel_set = 0;

        nzoneAsEval = -1;
        iterationAsEval = -1; 

        TeUsedColl = -1;
        TeUsedBoltz = -1;

        lgEvaluated = false;

        /* zero out array used to save emission line intensities */
        H2_SaveLine.zero();

        /* this was option to print all electronic states in the main printout - but
         * number of electronic states was not known at initialization so set to -1,
         * will set properly now */
        if( nElecLevelOutput < 1 )
                nElecLevelOutput = n_elec_states;

        return;
}

/*Yan_H2_CS - cross sections for the photoionization of H2 
 * may be represented analytically in the paper 
 *>>refer       H2      photo cs        Yan, M.; Sadeghpour, H. R.; Dalgarno, A. 1998, ApJ, 496, 1044
 * This is revised version given in ERRATUM 2001, ApJ, 559, 1194 
 * return value is photo cs in cm-2 */
double Yan_H2_CS( double energy_ryd /* photon energy in ryd */)
{

        double energy_keV; /* keV */
        double cross_section; /* barns */
        double x; /* x = E/15.4 */
        double xsqrt , x15 , x2;
        double energy = energy_ryd * EVRYD;

        DEBUG_ENTRY( "Yan_H2_CS()" );

        /* energy relative to threshold */
        x = energy / 15.4;
        energy_keV = energy/1000.0;
        xsqrt = sqrt(x);
        x15 = x * xsqrt;
        x2 = x*x;

        if( energy < 15.4 )
        {
                cross_section = 0.;
        }

        else if(energy >= 15.4 && energy < 18.)
        {
                cross_section = 1e7 * (1 - 197.448/xsqrt + 438.823/x - 260.481/x15 + 17.915/x2);
                /* this equation is obviously negative for x = 1 */
                cross_section = MAX2( 0. , cross_section );
        }

        else if(energy >= 18. && energy <= 30.)
        {
                cross_section = (-145.528 +351.394*xsqrt - 274.294*x + 74.320*x15)/pow(energy_keV,3.5);
        }

        else if(energy > 30. && energy <= 85.)
        {
                cross_section = (65.304 - 91.762*xsqrt + 51.778*x - 9.364*x15)/pow(energy_keV,3.5);
        }

        /* the high-energy tail */
        else 
        {
                cross_section = 45.57*(1 - 2.003/xsqrt - 4.806/x + 50.577/x15 - 171.044/x2 + 231.608/(xsqrt*x2) - 81.885/(x*x2))/pow(energy_keV,3.5);
        }

        return( cross_section * 1e-24 );
}

void diatomics::CalcPhotoionizationRate(void)
{
        DEBUG_ENTRY( "diatomics::CalcPhotoionizationRate()" );

        /* must reevaluate During search phase */
        if( ( nzone_eval!=nzone || iteration_evaluated!=iteration ) || !nzone )
        {
                t_phoHeat photoHeat;
                /* generally not important, do one time per zone */
                photoionize_rate = 
                        GammaK( ip_photo_opac_thresh,
                                rfield.nupper,
                                ip_photo_opac_offset,1.,
                                &photoHeat)*
                        ionbal.lgPhotoIoniz_On +
                        /* Compton recoil ionization - we include this in the H2 photoionization
                         * rate but not the heating rate - factor of two since assume 2H
                         * is same as two H0 at such high energies */
                        2.*ionbal.CompRecoilIonRate[ipHYDROGEN][0];
                        
                /* photo heating - this has units s-1 - needs H2 density
                 * to become vol heat rate */
                photo_heat_soft = photoHeat.HeatLowEnr * ionbal.lgPhotoIoniz_On;
                photo_heat_hard = photoHeat.HeatHiEnr * ionbal.lgPhotoIoniz_On;
                nzone_eval = nzone;
                iteration_evaluated = iteration;
        }

        return;
}