H2O

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Species data

Common Formula	H2O
Stoichiometric Formula	H2O
Name	Water
Mass	18.01056 a.m.u
Charge	0
CAS	7732-18-5
Inchi	InChI=1S/H2O/h1H2
InchiKey	XLYOFNOQVPJJNP-UHFFFAOYSA-N
State	Ground State

Search all reactions with H2O

KIDA H2O

ISM Abundance

log₁₀ Abundance	Reference	Source Name	Source Type	Link

Polarizability

Evaluation	Definition	Value (Å³)	Method	Origin	Reference
	xx	1.344	Calculations	Bibliography	Woon, D. E. et al. ;2009;Astrophysical Journal Supplement Series ;185,273-288
	yy	1.478	Calculations	Bibliography	Woon, D. E. et al. ;2009;Astrophysical Journal Supplement Series ;185,273-288
	zz	1.397	Calculations	Bibliography	Woon, D. E. et al. ;2009;Astrophysical Journal Supplement Series ;185,273-288
	total	1.501	Measurements	Database : NIST COMPUTATIONAL CHEMISTRY COMPARISON AND BENCHMARK DATABASE

Definition: xx Value (Å³): 1.344 Method: Calculations Origin: Bibliography Reference: Woon, D. E. et al. ;2009;Astrophysical Journal Supplement Series ;185,273-288
Definition: yy Value (Å³): 1.478 Method: Calculations Origin: Bibliography Reference: Woon, D. E. et al. ;2009;Astrophysical Journal Supplement Series ;185,273-288
Definition: zz Value (Å³): 1.397 Method: Calculations Origin: Bibliography Reference: Woon, D. E. et al. ;2009;Astrophysical Journal Supplement Series ;185,273-288
Definition: total Value (Å³): 1.501 Method: Measurements Origin: Database : NIST COMPUTATIONAL CHEMISTRY COMPARISON AND BENCHMARK DATABASE Reference:

Dipole moment

Evaluation	Value (D)	Method	Origin	Reference
	1.8546 ±0.004	Measurements	Bibliography	Lide, D. R.. ;2004;

Value (D): 1.8546 ±0.004 Method: Measurements Origin: Bibliography Reference: Lide, D. R.. ;2004;

Enthalpy of formation

Evaluation	T (K)	Value (kJ.mol^-1)	Method	Origin	Reference
	0	-238.922 ±0.03	Reviews and Evaluations	Database : Burcat
	298	-241.826 ±0.03	Reviews and Evaluations	Database : Burcat
	298	-241.81 ±0.03	Measurements	Database : CCCBDB (http://cccbdb.nist.gov/)
	0	-238.9 ±0.03	Measurements	Database : CCCBDB (http://cccbdb.nist.gov/)

T (K): 0 Value (kJ.mol^-1) : -238.922 ±0.03 Method: Reviews and Evaluations Origin: Other database Reference:
T (K): 298 Value (kJ.mol^-1) : -241.826 ±0.03 Method: Reviews and Evaluations Origin: Other database Reference:
T (K): 298 Value (kJ.mol^-1) : -241.81 ±0.03 Method: Measurements Origin: Other database Reference:
T (K): 0 Value (kJ.mol^-1) : -238.9 ±0.03 Method: Measurements Origin: Other database Reference:

Desorption energy

Evaluation	E_mean (K)	E_min (K)	E_max (K)	Pre-exponential factor (s^-1)	Order factor	Method	Origin	Reference	Type of surface	Description
	5600 ±1680	0	0	0.00E+0	1	Calculations	Bibliography	Wakelam, V. et al. ;2017;ArXiv e-prints;,	H2O	To estimate the unknown binding energies (for most of the radicals for example), we have developed a model founded on the stabilization energy of the complex between the various species and one water molecule. Then, we assume that the binding energy of the species with ASW is proportional to the energy of interaction between this species and one water molecule. To determine the proportionality coefficients, we fit the dependency of the experimental binding energies versus the calculated energies of the complexes for 16 stable molecules. Uncertainties in ED is estimated to be 30%. The preexponential factor is to be computed using the Hasegawa et al. (1992) approximation.
	5705			4.96E+15	1	Reviews and Evaluations	Bibliography	Minissale, Marco et al. ;2022;ACS Earth and Space Chemistry;,	Compact Amorphous Solid Water	Uncertainties are discussed in Minissale et al. (2022)
	5792			4.96E+15	1	Reviews and Evaluations	Bibliography	Minissale, Marco et al. ;2022;ACS Earth and Space Chemistry;,	Highly-Oriented Pyrolytic Graphite	Uncertainties are discussed in Minissale et al. (2022)
	5755			4.96E+15	1	Reviews and Evaluations	Bibliography	Minissale, Marco et al. ;2022;ACS Earth and Space Chemistry;,	Olivine	Uncertainties are discussed in Minissale et al. (2022)
	5700	0	0	0.00E+0	1	Estimation	Database : OSU		H2O	This binding energy was listed in the original OSU gas-grain code from Eric Herbst group in 2006. The pre-exponential factor is not given. It can be computed using the formula given in Hasegawa et al. (1992).

E_mean (K): 5600 ±1680 E _min (K): 0 E _max (K): 0 Pre-exponential factor (s^-1): 0.00E+0 Method: Calculations Origin: Bibliography Reference: Wakelam, V. et al. ;2017;ArXiv e-prints;, Type of surface: H2O Description: To estimate the unknown binding energies (for most of the radicals for example), we have developed a model founded on the stabilization energy of the complex between the various species and one water molecule. Then, we assume that the binding energy of the species with ASW is proportional to the energy of interaction between this species and one water molecule. To determine the proportionality coefficients, we fit the dependency of the experimental binding energies versus the calculated energies of the complexes for 16 stable molecules. Uncertainties in ED is estimated to be 30%. The preexponential factor is to be computed using the Hasegawa et al. (1992) approximation. Evaluation:
E_mean (K): 5705 E _min (K): E _max (K): Pre-exponential factor (s^-1): 4.96E+15 Method: Reviews and Evaluations Origin: Bibliography Reference: Minissale, Marco et al. ;2022;ACS Earth and Space Chemistry;, Type of surface: Compact Amorphous Solid Water Description: Uncertainties are discussed in Minissale et al. (2022) Evaluation:
E_mean (K): 5792 E _min (K): E _max (K): Pre-exponential factor (s^-1): 4.96E+15 Method: Reviews and Evaluations Origin: Bibliography Reference: Minissale, Marco et al. ;2022;ACS Earth and Space Chemistry;, Type of surface: Highly-Oriented Pyrolytic Graphite Description: Uncertainties are discussed in Minissale et al. (2022) Evaluation:
E_mean (K): 5755 E _min (K): E _max (K): Pre-exponential factor (s^-1): 4.96E+15 Method: Reviews and Evaluations Origin: Bibliography Reference: Minissale, Marco et al. ;2022;ACS Earth and Space Chemistry;, Type of surface: Olivine Description: Uncertainties are discussed in Minissale et al. (2022) Evaluation:
E_mean (K): 5700 E _min (K): 0 E _max (K): 0 Pre-exponential factor (s^-1): 0.00E+0 Method: Estimation Origin: Other database Reference: Type of surface: H2O Description: This binding energy was listed in the original OSU gas-grain code from Eric Herbst group in 2006. The pre-exponential factor is not given. It can be computed using the formula given in Hasegawa et al. (1992). Evaluation:

Diffusion energy

Evaluation	E (K)	Pre-exponential factor (cm² s^-1)	Method	Origin	Reference	Substrate	Type of diffusion	Description
	3036 ±156	2.20E-1	Measurements	Bibliography	Ghesquiere, P. et al. ;2015;Phys. Chem. Chem. Phys.;17, 11455-11468	H2O ice / Amorphous	Bulk	Arrhenius fit of experimental data for temperatures between 90 and 170K. The pre-exponantiel factor was fixed to 0.22 cm2 s-1.

E (K): 3036 ±156 Pre-exponential factor (cm² s^-1): 2.20E-1 Method: Measurements Origin: Bibliography Reference: Ghesquiere, P. et al. ;2015;Phys. Chem. Chem. Phys.;17, 11455-11468 Substrate: H2O ice / Amorphous Type of diffusion: Bulk Description: Arrhenius fit of experimental data for temperatures between 90 and 170K. The pre-exponantiel factor was fixed to 0.22 cm2 s-1. Evaluation: