title check rate H2 forms on grain surfaces 
c
c commands controlling continuum =========
c first continuum is FIR hot grain continuum produced in 
c unmodeled HII Region
blackbody, t = 75 K
intensity 2.7 (total)
c this is hot star continuum
black 30000
intensity  1.90 range  0.4412 to 1 Ryd
c this will remove all ionizing radiation
extinguish 24 0
cosmic rays, background
c
c commands for density & abundances =========
hden 0
grains ism, abundance log 0.16 no qheat 
init file="ism.ini"
abundances he -1.01 c -3.52 n-8 o-3.30 ne-8 mg-5.89
continue si -6.10 s -5.10 cl=-7 ar-8 fe -6.60
c
c commands controlling geometry  =========
sphere
c stop when gas is fully neutral
stop efrac -10
c stop when gas is cold
stop temperature 10 linear
stop zone 1 
c
c other commands for details     =========
c set the gas temperature
constant temperature 100 K
case b
c
c commands controlling output    =========
normalize to "C  2" 157.6m 
c uv lines are strongly pumped by stellar continuum, break out contribution
print line pump
print line optical depths
print ages
save overview "ism_jura.ovr"
save performance "ism_jura.per"
save monitors last "ism_jura.asr"
save hydrogen 21 cm last "ism_jura.21cm"
c
c commands giving the monitors    =========
// >>chng 03 jan 12, from -16.523 to -16.583, dist grains
// Jura rate was 3e-17 s-1
monitor grain h2 rate -16.583
c ism_jura.in
c class limit  
c ========================================
c 

This model started out life as the Tielens & Hollenbach 1985 pdr.  The
density was set to unity and the incident radiation field adjusted so
that the two default grains have temperatures near 100K.  The model
asserts that the H2 formation rate on grain surfaces is close to the
//>>refer	H2	grain physics	Jura, M., 1975, ApJ, 197, 575
rate.
