title illumination by cool STE blackbody
c gasis fully molecular, grains should be in STE
c
c commands controlling continuum =========
c illuminate with 120 blackbody in thermodynamic equilibrium
blackbody 120 STE
CMB  
c 
c commands for density & abundances =========
c density
hden 7
c ism dust and grains
abundances ISM no grains
c dust to gas ratio is 10x standard
grains 1.0
c lowers metals and grains to 1/10 standard, so metals are
c 1/10 solar while dust to gas ratio is galactic
metals and grains 0.1
c
c other commands for details     =========
c CO heating sets dr on second iteration, need many zones
set nend 1600
c set background cosmic rays to allow chemistry 
cosmic ray background 
iterate
c
c commands controlling geometry  =========
radius 17.5
sphere
stop temperature 20K linear 
stop column density 25.5
c
c commands controlling output    =========
save performance "pdr_coolbb.per"
save overview "pdr_coolbb.ovr"
save monitors "pdr_coolbb.asr" last
save molecules "pdr_coolbb.mol"
save heating "pdr_coolbb.het"
save cooling "pdr_coolbb.col"
save dr "pdr_coolbb.dr"
save grain temperature "pdr_coolbb.grntem"
c
c commands giving the monitors    =========
// >>chng 12 jun 07, from 59.1 to 56.42, vib_evap fix
monitor temperature hydrogen 1 56.42
monitor H2 column density 25.20 
monitor CO column density 20.89 error 0.1 
//
// >>chng 08 feb 20, from -1.123 to -1.475, grain charge transfer changes in ion_solver and iso*
// >>chng 08 jun 25, from -1.475 to -1.43 add source/sink to ioniz ladder
// >>chng 11 nov 16, from -1.43 to -1.255, adjust newmole monitors
// >>chng 12 apr 09, from -1.255 to -0.5646, update CR backbround to Indriolo+07, ~8x larger
// >>chng 12 jun 07, from -0.5646 to -0.6186, vib_evap fix
// >>chng 12 jul 17, from -0.6186 to -0.5746, minor changes due to r6414
// >>chng 12 aug 16, from -0.5746 to -0.6182, fix radasc bug from r6346
// >>chng 12 aug 16, from -0.6182 to -0.5722, further fix of Rawlings H2 rates
// >>chng 12 oct 26, from -0.5722 to -0.6358, adjust montiors to this branch
// >>chng 12 nov 01, from -0.6358 to -0.5872, Chianti experimental levels, revised Badnell DR suppression
monitor eden -0.5872 error 0.1
//
// >>chng 08 dec 08, from 9 to 4.214, upper limit -> equals (r2515)
// >>chng 08 dec 13, from 4.214 to 9.777, merging newsolvers branch
// >>chng 09 jan 16, from 9.777 to 9.823 (error 0.03), average of 10 runs
// >>chng 09 jan 22, from 9.823 to 10.19, some minor botches as a result of r2655
// >>chng 09 dec 09, from 10.19 to 9.84, array overrun fix
// >>chng 11 jun 22, from 9.84 to 7.81, tune Te solver
// >>chng 12 oct 22, from 7.81 to 10.57, zone tau in rt_line_one
monitor itrzn 10.57
//
// >>chng 09 oct 25, add this monitor
// >>chng 09 dec 09, from 1412 to 385 array overrun fix
// >>chng 10 mar 02, from 385 to 363, fix botches after CO model switch
// >>chng 10 jun 25, from 383 to 384 Ryan's species cooling bugfix
// >>chng 12 jun 07, from 384 to 408, vib_evap fix
// >>chng 12 oct 22, from 408 to 453, zone tau in rt_line_one
monitor nzone 453
c
c pdr_coolbb.in
c class pdr 
c ========================================

This is a dense ISM exposed to a cool blackbody.  This tests the
ability to converge onto a VERY molecular environment.  Nearly all
C and H are in CO and H2.  Cosmic rays are the main source of
heat and ionization.

Continuum pumping of CO followed by collisional deexcitation is a
major heating agent across the sim.