Changeset 1729

Timestamp:

01/04/08 12:55:28 (11 months ago)

Author:

rjrw

Message:

Initial implementation of finite surface saturation of grain
photodesorption.

Location:

branches/newmole/source

Files:

• mole.h (modified) (1 diff)
• mole_reactions.cpp (modified) (2 diffs)
• mole_species.cpp (modified) (2 diffs)

branches/newmole/source/mole.h

@@ -107 +107 @@
         int num_total, num_calc, num_compacted;
         
-        realnum eden_f, grain_area;
+        realnum eden_f, grain_area, grain_density, grain_saturation;
 
         /** total charge in molecules */

branches/newmole/source/mole_reactions.cpp

@@ -961 +961 @@
         /* Compute thermal evaporation terms along with total dust number density */
         fixit(); // should there be an area weighting to exponential terms?
-        if( conv.nTotalIoniz > 1 || iteration > 1 )
-        {
-                for( nd=0; nd < gv.nBin; nd++ )
-                {
-                        Exp_i += exp(-E_i/gv.bin[nd]->tedust);
-                        Exp_j += exp(-E_j/gv.bin[nd]->tedust);
-                        dust_density += gv.bin[nd]->IntArea*gv.bin[nd]->cnv_H_pCM3/(4*PI*(1e-10));
-                }
+
+        for( nd=0; nd < gv.nBin; nd++ )
+        {
+                Exp_i += exp(-E_i/gv.bin[nd]->tedust);
+                Exp_j += exp(-E_j/gv.bin[nd]->tedust);
+                dust_density += gv.bin[nd]->IntArea*gv.bin[nd]->cnv_H_pCM3/(4*PI*(1e-10));
         }
         
+        ASSERT(fp_equal(dust_density,mole.grain_area/(PI*1e-10)));
+
         /* rates of migration on surface for each species */
         diff_i = (1/total_sites)*vib_freq_i*Exp_i;
@@ -1002 +1002 @@
         // 1.232e7f * 1.71f is from DB96 referred to below 
         // will be multiplied by yield factor (~1e-4) to get overall photodesorption rate
-        return 2e-15 * hmi.UV_Cont_rel2_Draine_DB96_depth *(1.232e7f * 1.71f);
+        return mole.grain_saturation*2e-15 * hmi.UV_Cont_rel2_Draine_DB96_depth *(1.232e7f * 1.71f);
 }
 

branches/newmole/source/mole_species.cpp

@@ -596 +596 @@
         int i;
         int nd;
-        double den_times_area;
+        double den_times_area, den_grains, adsorbed_density;
 
         DEBUG_ENTRY("mole_update_species_cache()");
 
         mole.eden_f = (realnum)dense.eden;  /* Need floating point version for compatibility with all other values */
+
+        for (i=0;i<mole.num_total;i++) 
+        {
+                if(COmole[i]->location != NULL) 
+                        COmole[i]->hevmol = *(COmole[i]->location);
+        }
  
         /* For rates that are dependent on grain physics.  This includes grain density, 
@@ -613 +619 @@
         if(gv.lgDustOn)
         {
-                den_times_area = 0.0;
+                den_times_area = den_grains = 0.0;
                 for( nd=0; nd < gv.nBin; nd++ )
                 {
                         /* >>chng 06 mar 04, update expression for projected grain surface area, PvH */
                         den_times_area += gv.bin[nd]->IntArea/4.*gv.bin[nd]->cnv_H_pCM3;
+                        den_grains += gv.bin[nd]->cnv_GR_pCM3;
                 }
                 
+                adsorbed_density = 0.0;
+                for (i=0;i<mole.num_total;i++) 
+                {
+                        if( !COmole[i]->lgGas_Phase ) 
+                                adsorbed_density += COmole[i]->hevmol;
+                }
+
                 mole.grain_area = den_times_area;
+                mole.grain_density = den_grains;
+
+                double mole_cs = 1e-15;
+                if (4*den_times_area >= mole_cs*adsorbed_density)
+                        mole.grain_saturation = 1.0;
+                else
+                        mole.grain_saturation = 4*den_times_area/(mole_cs*adsorbed_density);
         }
         else
         {
                 mole.grain_area = 0.0;
-        }
-
-        for (i=0;i<mole.num_total;i++) 
-        {
-                if(COmole[i]->location != NULL) 
-                        COmole[i]->hevmol = *(COmole[i]->location);
-        }
+                mole.grain_density = 0.0;
+                mole.grain_saturation = 1.0;
+        }
+
 }