SPEX Reference manual (PDF) - SRON

3.3 Amol: oxygen edge molecules absorption model 51
1. The location of the absorption edges is not always fully correct; this can be seen with high resdolution
grating spectra
2. The model fails in the optical/UV band (i.e., it does not become transparent in the optical)
3. No absorption lines are taken into account
4. The abundances cannot be adjusted
If all the above is of no concern (as is the case in many situations), then the Morrison & McCammon
model is very useful. In case higher precision or more detail is needed, the user is advised to use the
”hot”model with lowtemperaturein SPEX,which givesthe transmissionofaslabin collisionalionisation
equilibrium.
The parameters of the model are:
nh - Hydrogen column density in 10 28 m −2 . Default value: 10 −4 (corresponding to 10 24 m −2 , a typical
value at low Galactic latitudes).
f - The covering factor of the absorber. Default value: 1 (full covering)
3.3 Amol: oxygen edge molecules absorption model
This model calculates the transmission of various molecules.
The following compounds are presently taken into account (see Table 3.2).
Table 3.2: Molecules present in the amol model.
nr name chemical formula atom & shell reference
108 molecular oxygen O 2 O 1s a
114 silicon crystal Si Si 1s h
126 metallic iron Fe Fe 1s,2p i,j
2001 water H 2 O O 1s c
2002 crystalline ice H 2 O O 1s d
2003 amorphous ice H 2 O O 1s d
2010 carbon monoxide CO O 1s a
2011 carbon dioxide CO 2 O 1s a
2020 laughing gas N 2 O O 1s a,b
2100 silicon carbide SiC Si 1s h
2101 silicon nitrite Si 3 N 4 Si 1s h
2102 silicon monoxide SiO Si 1s h
2103 quartz SiO 2 Si 1s h
2104 silica SiO 2 Si 1s h
2200 eskolaite Cr 2 O 3 O 1s e
2300 iron monoxide FeO Fe 1s i
2301 iron oxide Fe 1−x O O 1s e
2302 magnetite Fe 3 O 4 O, Fe 1s e,i
2303 hematite Fe 2 O 3 O, Fe 1s; Fe 2p e,i,j
2304 iron sulfite FeS 2 Fe 1s i
2400 nickel monoxide NiO O 1s e
2500 cupric oxide CuO O 1s e
3001 adenine C 5 H 5 N 5 O 1s f
3100 enstatite MgSiO 3 Si 1s h
3101 enstatite alfa MgSiO 3 Si 1s h
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