Chemical Network

The table below shows the reactions in Grackle`s chemical network. All reactions are of the form left-hand side (LHS) -> right-hand side (RHS). The rate column corresponds to the interval table responsable for the reaction rate. The citation colomns denotates the publication in which reaction rate appears in the form used within Grackle. Note, some reaction rate have multiple options depending on the setting of various parameters.

LHS	RHS	Rate	Citation	Enabled By
H + e-	H+ + e- + e-	k1	Abel et al. (1997)	primordial_chemistry >0
H+ + e-	H + \({\gamma}\)	k2	Abel et al. (1997) & Hui & Gnedin (1997)	primordial_chemistry >0
He + e-	He+ + e- + e-	k3	Abel et al. (1997)	primordial_chemistry >0
He+ + e-	He+ + \({\gamma}\)	k4	Hui & Gnedin (1997) & Aldrovandi & Pequignot (1973) & Black (1981)	primordial_chemistry >0
He+ + e-	He++ + e- + e-	k5	Abel et al. (1997)	primordial_chemistry >0
He++ + e-	He+ + \({\gamma}\)	k6	Hui & Gnedin (1997) & Cen (1992)	primordial_chemistry >0
H + H	H+ + e- + H	k57	Lenzuni, Chernoff & Salpeter (1991)	primordial_chemistry >0
H + He	H+ + e- + He	k58	Lenzuni, Chernoff & Salpeter (1991)	primordial_chemistry >0
H + \({\gamma}\)	H+ + e-	-	none	primordial_chemistry >0
He + \({\gamma}\)	He+ + e-	-	none	primordial_chemistry >0
He+ + \({\gamma}\)	He+ + + e-	-	none	primordial_chemistry >0
H + e-	H- + \({\gamma}\)	k7	Stancil et al. (1998)	primordial_chemistry >1
H- + H	H2 + e-	k49	Kreckel et al. (2010)	primordial_chemistry >1
H + H+	H2+ + \({\gamma}\)	k9	Latif et al. (2015)	primordial_chemistry >1
H2+ + H	H2 + H+	k10	Karpas, Anicich & Huntress (1979)	primordial_chemistry >1
H2 + H+	H2+ + H	k11	Savin et al. (2004a; b)	primordial_chemistry >1
H2 + e-	H + H + e-	k12	Trevisan & Tennyson (2002)	primordial_chemistry >1
H2 + H	H + H + H	k13	Martin, Schwarz & Mandy (1996)	primordial_chemistry >1
H- + e-	H + e- + e-	k14	Abel et al. (1997)	primordial_chemistry >1
H- + H	H + e- + H	k15	Abel et al. (1997)	primordial_chemistry >1
H- + H+	H + H	k16	Croft, Dickinson & Gadea (1999)	primordial_chemistry >1
H- + H+	H2+ + e-	k17	Abel et al. (1997) & Shapiro & Kang. (1987)	primordial_chemistry >1
H2+ + e-	H + H	k18	Abel et al. (1997)	primordial_chemistry >1
H2+ + H-	H2 + H	k19	Dalgarno & Lepp (1985)	primordial_chemistry >1
2H + H2	2H2	k21	Cohen & Westberg (1983)	primordial_chemistry >1
3H	H2 + H	k22	see table below	primordial_chemistry >1
H + \({\gamma}\)	H+ + e-	k24	none	primordial_chemistry >0
He+ + \({\gamma}\)	He++ + e-	k25	none	primordial_chemistry >0
He + \({\gamma}\)	He+ + e-	k26	none	primordial_chemistry >0
H- + \({\gamma}\)	H + e-	k27	none	primordial_chemistry >1
H2+ + \({\gamma}\)	H + H+	k28	none	primordial_chemistry >1
H2 + \({\gamma}\)	H2+ + e-	k29	none	primordial_chemistry >1
H2+ + \({\gamma}\)	H+ + H+ + e-	k30	none	primordial_chemistry >1
H2 + \({\gamma}\)	H + H	k31	none	primordial_chemistry >1
H + H + grain	H2 + grain	k2dust	Tielens & Hollenbach (1985)	primordial_chemistry >1 & h2_on_dust ==1
H+ + D	H + D+	k50	Savin (2002)	primordial_chemistry >2
D+ + H	D + H+	k51	Savin (2002)	primordial_chemistry >2
H2 + D+	HD + H+	k52	Galli & Palla (2002)	primordial_chemistry >2
HD + H+	H2 + D+	k53	Galli & Palla (2002)	primordial_chemistry >2
H2 + D	HD + H	k54	Clark et al. (2011)	primordial_chemistry >2
HD + H	H2 + D	k55	Galli & Palla (2002) & Ripamonti (2007)	primordial_chemistry >2
D + H-	HD + e-	k56	Kreckel et al. (2010)	primordial_chemistry >2

Note

For equations with \({\gamma}\) on the LHS, the rate for this equation come sfrom the choice of UV background models. See UVBackground for more information.

This table below maps the chemical species used above to the relevent Grackle field pointers.

Chemical Species

variable	Reaction Network
H	HI_density
H+	HII_density
H-	HM_density
H2	H2I_density
H2+	H2II_density
He	HeI_density
He+	HeII_density
He++	HeIII_density
e-	e_density
D	DI_density
D+	DII_density
HD	HDI_density

K22 Citations

k22 three-body-rate	Citations
0	Abel, Bryan & Norman (2002)
1	Palla, Salpeter & Stahler (1983)
2	Cohen & Westberg (1983)
3	Flower & Harris (2007)
4	Glover (2008)
5	Forrey (2013)