National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
XOlder CCCBDB versions
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers

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II.A.1. (XV.A.)

Listing of experimental data for H2OH2O (water dimer)

Other names
State Conformation
1A' CS
Enthalpy of formation (Hfg), Entropy, Integrated heat capacity (0 K to 298.15 K) (HH), Heat Capacity (Cp)
Property Value Uncertainty units Reference Comment
Information can also be found for this species in the NIST Chemistry Webbook
Vibrational levels (cm-1) vibrations
Mode Number Symmetry Frequency (cm-1) Frequency Reference Intensity (km mol-1) Int. unc. Intensity Reference Comment
1 A' 3735 2006Dun/Eva:303      
2 A' 3660 2006Dun/Eva:304      
3 A' 3601 2006Dun/Eva:305      
4 A' 1616 2006Dun/Eva:306      
5 A' 1599 2006Dun/Eva:307      
6 A' 311 2006Dun/Eva:308      
7 A' 143 2006Dun/Eva:309      
8 A' 103 2006Dun/Eva:310      
9 A" 3745 2006Dun/Eva:311      
10 A" 523 2006Dun/Eva:312      
11 A" 108 2006Dun/Eva:313      
12 A" 88 2006Dun/Eva:314      

vibrational zero-point energy: 9616.0 cm-1
Calculated vibrational frequencies for H2OH2O (water dimer).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment

Calculated rotational constants for H2OH2O (water dimer).

Product of moments of inertia moments of inertia
amu3Å6   0gm3 cm6
Geometric Data
picture of water dimer

Point Group Cs

Internal coordinates
distances (r) in Å, angles (a) in degrees, dihedrals (d) in degrees

Description Value unc. Connectivity Reference Comment
Atom 1 Atom 2 Atom 3 Atom 4
rOO 2.976 0.030 2 3 1980Odu/Dyk:5062 +0.000 -0.030
aOOX 51 10 3 2 7 1980Odu/Dyk:5062 X is on donor aHOH bisector
aOOX 57 10 2 3 8 1980Odu/Dyk:5062 X is on acceptor aHOH bisector


Atom x (Å) y (Å) z (Å)

Atom - Atom Distances bond lengths
Distances in Å


Calculated geometries for H2OH2O (water dimer).

Bond descriptions

Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond
Bond Type Count
H-O 4
H.O 1


Atom 1 Atom 2
H1 O2
H1 O3
O2 H4
O3 H5
O3 H6
Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 1   1A'

Ionization Energies (eV)

Ionization Energy I.E. unc. vertical I.E. v.I.E. unc. reference
11.210 0.090     webbook
Dipole, Quadrupole and Polarizability
Electric dipole moment dipole
Calculated electric dipole moments for H2OH2O (water dimer).
Electric quadrupole moment quadrupole
Calculated electric quadrupole moments for H2OH2O (water dimer).

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squib reference DOI
1980Odu/Dyk:5062 JA Odutola, TR Dyke "PARTIALLY DEUTERATED WATER DIMERS - MICROWAVE-SPECTRA AND STRUCTURE" J. Chem. Phys. 72(9), 5062-5070, 1980 10.1063/1.439795
webbook NIST Chemistry Webbook (  

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