title test of H and HeI ionization in optically thin limit
c
c commands controlling continuum =========
laser 2.0 Ryd
// >>chng 02 ocg 27, use lumin instead so that this
// part of cont norm is also tested for laser
intensity -0.3604
c
c commands for density & abundances =========
hden 1
init file="hheonly.ini"
abundances all -10
c
c commands controlling geometry  =========
stop zone 1
set dr 0
c
c other commands for details     =========
constant temperature = 4
iterate to convergence
c
c commands controlling output    =========
save overview "limit_laser_2.ovr"
save performance "limit_laser_2.per"
save monitors "limit_laser_2.asr" last
c
c commands giving the monitors    =========
monitor ionization hydrogen 1 -3.34
// >>chng 11 sep 15, from -4.18 to -4.159, Chianti for Fe moderate to high ions
monitor ionization helium 1 -4.159
monitor niter 3 error 0.01
c limit_laser_2.in
c class limit  
c ========================================
c 

This checks the calculation of the hydrogen and helium photoionization
equilibrium. The continuum is a laser peaked at 2.0 Ryd, and so can
only ionize hydrogen and atomic helium. 

Checks:
-	The hydrogen neutral fraction is nearly Ho/H+=4.51*10-4
	(not exact since laser has finite width).
-	Hb emissivity close to high density case A.  The predicted TOTL 4861
	intensity should be nearly 2.2 times the expected case B intensity.
-	Helium ionization should be Heo/He+ = 6.61*10-4.

H cross section is 0.927E-18 cm^2, rec coef is 4.18E-13
answer is Ho/H+ = 4.51e-4
HeI cross section is 6.54E-18 cm^2, rec coef is 4.32E-13
answer is Heo/He+ = 6.61e-5