title low density and flux model 1 
atom H2 He collisions new 
c
c commands controlling continuum =========
c Use the Draine 1978 field, for a semi-infinite slab we have to use half
c the requested value, so the actual value
c they want for the model is actually twice the value below
table draine 5
c this is to insure that no H-ionizing radiation strikes the cloud
extinguish 24 
c
c commands for density & abundances =========
c  hydrogen density 
hden 3.
grains ism 1.16 no qheat
c
c commands controlling geometry  =========
c
c other commands for details     =========
c turn on the large H2 model
atom h2 
c turn down the number of convergence failures - there should be none
failures 3
c use leiden initialization file
init file="pdr_leiden.ini"
c This command defines the grain temperature to be a constant 20 Kelvin
constant grain temperature 20 
c This sets the gas kinetic temperature to a constant 50 Kelvin
constant temperature 50 linear
c
c commands controlling output    =========
c default normalization line is Hbeta, which is not produced by this gas
normalize to "C  2" 157.6m
print line faint -4 
save performance "h2_pdr_leiden_f1.per"
save overview "h2_pdr_leiden_f1.ovr"
// show how emission varies across structure
save line emissivity "h2_pdr_leiden_f1.ems" 
H2   2.121m
CO   650.1m
C  2 157.6m
O  1 63.17m
Si 2 34.81m
end of lines
// 
save leiden lines "h2_pdr_leiden_f1.lin"
save leiden "h2_pdr_leiden_f1.lei"
save dr "h2_pdr_leiden_f1.dr" 
save molecules "h2_pdr_leiden_f1.mol"
save grain physical conditions "h2_pdr_leiden_f1.grn"
save overview "h2_pdr_leiden_f1.ovr"
save monitors "h2_pdr_leiden_f1.asr"
save H2 lines "h2_pdr_leiden_f1.h2lin" all
save H2 column density "h2_pdr_leiden_f1.h2col"
save H2 populations matrix zone "h2_pdr_leiden_f1.pop"
save H2 rates "h2_pdr_leiden_f1.rat"
save dominant rates "h2_pdr_leiden_f1.h2" "H2" 
save chemistry rates "h2_pdr_leiden_f1.h2d" "H2" destruction
c
c commands giving the monitors    =========
monitor H2 column density 21.90 error 0.1
//
// >>chng 05 jul 02, from 18.01 to 17.96, stop AV was not exact
// >>chng 05 nov 22, from 17.96 to 16.35, NA add freeze out onto grains
// >>chng 05 dec 17, from 16.35 to 16.54, NA increase C chemistry
// >>chng 06 jan 04, from 16.54 to 16.65, NA C chem restore missed block reacts
// >>chng 06 mar 02, from 16.65 to 17.42, NA Fe0, Mg0, <-> Si+, S+, C+ ct,
// also energy barrier for H + (CH and CH2) reactions
// >>chng 06 mar 06, from 17.42 to 17.29, PvH grain freeze out
// >>chng 12 jun 07, from 17.29 to 17.01, vib_evap fix
monitor CO column density 17.01 error 0.2
// 
// >>chng 08 dec 08, from 5 to 2.396, upper limit -> equals (r2515)
// >>chng 08 dec 13, from 2.396 to 3.936, merging newsolvers branch
// >>chng 09 jan 16, from 3.936 to 3.944, average of 10 runs
// >>chng 09 feb 23, from 3.944 to 4.064, remove otslin, otscon dampers (PR #84, r2758)
// >>chng 09 mar 27, from 4.064 to 4.149 improve rigor esc prob & pop defns
// >>chng 09 apr 19, from 4.149 o 4.07, refactor p esc dest and cooling
// >>chng 11 nov 16, from 4.07 to 3.684, adjust newmole monitors
// >>chng 12 aug 16, from 3.684 to 3.512, further fix of Rawlings H2 rates
monitor itrzn 3.512 error 0.05
// 
// >>chng 05 jun 26, from 450 to 583 make Federman chem the default
// >>chng 05 aug 18, from 620 to 700, ? ?
// >>chng 06 mar 02, from 700 to 770 (737) NA Fe0, Mg0, <-> Si+, S+, C+ ct,
// also energy barrier for H + (CH and CH2) reactions
// >>chng 07 oct 29, from 770 to 619, change from "<" to "="
// >>chng 09 jan 16, from 619 to 622, average of 10 runs
// >>chng 11 nov 16, from 622 to 754, adjust newmole monitors
monitor nzone 754
// 
// these added 05 jan 22
monitor H2 column density level 0  0  21.79 error 0.1
// 
// >>chng 05 jun 21, from 21.26 to 21.29, chng cr, grn deex
monitor H2 column density level 0  1  21.29 error 0.1
// 
// >>chng 11 nov 16, from 18.04 to 15.28, adjust newmole monitors
// >>chng 12 jan 06, from 15.28 to 18.02, several H2 model changes
monitor H2 column density level 0  2  18.02 error 0.1
// 
// >>chng 05 jun 21, from 15.94 to 16.06, chng cr, grn deex
// >>chng 05 aug 03, from 16.06 to 15.98, NA update CO, H chem net
// >>chng 07 apr 07, from 15.98 to 15.91, update H2 cr to trip
// >>chng 07 apr 07, from 15.91 to 15.95, use ORNL H2-He collision set
// >>chng 11 apr 19, from 15.95 to 16, due to factor of 2 changes in some H2-H2 collisions.  Eq. 2 of Lee et al. 2008 (ApJ, 689, 1105)
// >>chng 11 nov 16, from 16 to 15.1, adjust newmole monitors
// >>chng 12 jan 06, from 15.1 to 16.01, several H2 model changes
monitor H2 column density level 0  3  16.01 error 0.1
// 
// >>chng 05 jun 21, from 15.01 to 15.17, chng cr, grn deex
// >>chng 07 apr 07, from 15.17 to 15.07, update H2 cr to trip
// >>chng 11 nov 16, from 15.07 to 15, adjust newmole monitors
monitor H2 column density level 0  4  15 error 0.1
// 
// >>chng 05 jun 21, from 14.59 to 14.72, chng cr, grn deex
// >>chng 05 aug 03, from 14.72 to 14.58, NA update CO, H chem net
// >>chng 07 apr 09, from 14.58 to 14.53, H2-He coll to ORNL data
// >>chng 07 apr 07, from 14.53 to 14.59, use ORNL H2-He collision set
// >>chng 11 nov 16, from 14.59 to 14.68, adjust newmole monitors
// >>chng 12 jan 06, from 14.68 to 14.61, several H2 model changes
monitor H2 column density level 0  5  14.61 error 0.1
// 
// >>chng 05 jun 21, from 13.70 to 13.84, chng cr, grn deex
// >>chng 05 aug 03, from 13.84 to 13.74, NA update CO, H chem net
// >>chng 07 apr 07, from 13.74 to 13.69, H2-He coll to ORNL data
// >>chng 07 apr 07, from 13.69 to 13.74, use ORNL H2-He collision set
// >>chng 11 nov 16, from 13.74 to 13.8, adjust newmole monitors
// >>chng 12 jan 06, from 13.8 to 13.75, several H2 model changes
monitor H2 column density level 0  6  13.75 error 0.1
// 
// >>chng 05 jun 21, from 13.70 to 13.78, chng cr, grn deex
// >>chng 05 aug 03, from 13.78 to 13.60, NA update CO, H chem net
// >>chng 07 apr 07, from 13.60 to 13.65, use ORNL H2-He collision set
// >>chng 11 nov 16, from 13.65 to 13.79, adjust newmole monitors
// >>chng 12 jan 06, from 13.79 to 13.69, several H2 model changes
monitor H2 column density level 0  7  13.69 error 0.15
// 
// >>chng 05 jun 21, from 12.84 to 12.98, chng cr, grn deex
// >>chng 05 aug 03, from 12.98 to 12.82, NA update CO, H chem net
// >>chng 07 apr 07, from 12.82 to 12.78, H2-He coll to ORNL data
// >>chng 07 apr 07, from 12.78 to 12.88, use ORNL H2-He collision set
// >>chng 11 nov 16, from 12.88 to 12.99, adjust newmole monitors
// >>chng 12 jan 06, from 12.99 to 12.92, several H2 model changes
monitor H2 column density level 0  8  12.92 error 0.1
// 
// >>chng 05 jun 21, from 13.01 to 13.11, chng cr, grn deex
// >>chng 05 aug 03, from 13.11 to 12.93, NA update CO, H chem net
// >>chng 07 apr 07, from 12.93 to 12.99, use ORNL H2-He collision set
// >>chng 11 nov 16, from 12.99 to 13.13, adjust newmole monitors
// >>chng 12 jan 06, from 13.13 to 13.01, several H2 model changes
monitor H2 column density level 0  9  13.01 error 0.15
// 
// >>chng 05 jun 21, from 12.10 to 12.25, chng cr, grn deex
// >>chng 05 aug 03, from 12.25 to 12.28, NA update CO, H chem net
// >>chng 07 apr 07, from 12.28 to 12.21, H2-He coll to ORNL data
// >>chng 07 apr 07, from 12.21 to 12.17, use ORNL H2-He collision set
// >>chng 11 nov 16, from 12.17 to 12.06, adjust newmole monitors
monitor H2 column density level 1  0  12.06 error 0.1
// 
// >>chng 05 jun 21, from 12.43 to 12.53, chng cr, grn deex
// >>chng 07 apr 07, from 12.53 to 12.44, update H2 cr to trip
// >>chng 08 sep 25, from 12.44 to 12.39, remove damper on line pump (r2367)
// >>chng 11 nov 16, from 12.39 to 12.27, adjust newmole monitors
monitor H2 column density level 1  1  12.27 error 0.1
// 
// >>chng 05 jun 21, from 12.51 to 12.66, chng cr, grn deex
// >>chng 05 aug 03, from 12.66 to 12.69, NA update CO, H chem net
// >>chng 07 apr 07, from 12.69 to 12.62, H2-He coll to ORNL data
// >>chng 08 mar 17, from 12.62 to 12.57, r1844 - mostly iso PopOpc and rt_line_one_tauinc changes
// >>chng 11 nov 16, from 12.57 to 12.23, adjust newmole monitors
// >>chng 12 jan 06, from 12.23 to 12.45, several H2 model changes
monitor H2 column density level 1  2  12.45 error 0.1
// 
// >>chng 05 jun 21, from 12.40 to 12.51, chng cr, grn deex
// >>chng 07 apr 07, from 12.51 to 12.41, update H2 cr to trip
// >>chng 11 nov 16, from 12.41 to 12.26, adjust newmole monitors
// >>chng 12 jan 06, from 12.26 to 12.31, several H2 model changes
monitor H2 column density level 1  3  12.31 error 0.1
c
c h2_pdr_leiden_f1.in
c class pdr  
c ========================================
c 

This is one of the tests in Rollig et al. 2007, A&A, 467, 187