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Experimental data for Ar2 (Argon diatomic)

22 02 02 11 45
State Conformation
1Sg D*H
Enthalpy of formation (Hfg), Entropy, Integrated heat capacity (0 K to 298.15 K) (HH), Heat Capacity (Cp)
Property Value Uncertainty units Reference Comment
Hfg(298.15K) enthalpy of formation     kJ mol-1 1976Col/Dou:1741-1745
Hfg(0K) enthalpy of formation -1.01   kJ mol-1 1976Col/Dou:1741-1745
Information can also be found for this species in the NIST Chemistry Webbook
Vibrational levels (cm-1) vibrations
Mode Number Symmetry Frequency Intensity Comment Description
Fundamental(cm-1) Harmonic(cm-1) Reference (km mol-1) unc. Reference
1 Σ 26 30 1976Col/Dou:1741      

Detailed diatomic data
ωe ωexe ωeye Be αe ZPE reference
29.75706 2.20388 -0.0209 0.05975 0.00375 derived from 1976Col/Dou:1741

vibrational zero-point energy: 12.9 cm-1 (from fundamental vibrations)
Calculated vibrational frequencies for Ar2 (Argon diatomic).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment
  0.05975   webbook

Calculated rotational constants for Ar2 (Argon diatomic).
Product of moments of inertia moments of inertia
282.1361amu Å2   4.685053E-38gm cm2
Geometric Data
picture of Argon diatomic

Point Group D∞h

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
rArAr 3.758   1 2 webbook

Atom x (Å) y (Å) z (Å)
Ar1 0.0000 0.0000 0.0000
Ar2 0.0000 0.0000 3.7580

Atom - Atom Distances bond lengths
Distances in Å
  Ar1 Ar2
Ar1   3.7580
Ar2 3.7580  

Calculated geometries for Ar2 (Argon diatomic).

Bond descriptions

Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond
Bond Type Count
Ar-Ar 1

Atom 1 Atom 2
Ar1 Ar2
Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 1   1Sg

Ionization Energies (eV)
Ionization Energy I.E. unc. vertical I.E. v.I.E. unc. reference
14.501 0.025 15.548 0.003 webbook
Dipole, Quadrupole and Polarizability
Electric dipole moment dipole
State Config State description Conf description Exp. min. Dipole (Debye) Reference comment Point Group Components
x y z total dipole quadrupole
1 1 1Sg D∞h True           D∞h 0 1
Experimental dipole measurement abbreviations: MW microwave; DT Dielectric with Temperature variation; DR Indirect (usually an upper limit); MB Molecular beam
Calculated electric dipole moments for Ar2 (Argon diatomic).
Electric quadrupole moment quadrupole
State Config State description Conf description Exp. min. Quadrupole (D Å) Reference comment Point Group Components
xx yy zz dipole quadrupole
1 1 1Sg D∞h True       D∞h 0 1

Calculated electric quadrupole moments for Ar2 (Argon diatomic).

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squib reference DOI
1976Col/Dou:1741 EQ Colburn, AE Douglas "The spectrum and ground statepotential curve of Ar2" J. Chem. Phys. 65, 1741, 1976 10.1063/1.433319
1976Col/Dou:1741-1745 EA Colbourn, and AE Douglas "The spectrum and ground state potential curve of Ar2" J. Chem. Phys. 65, 1741 (1976) 10.1063/1.433319
webbook NIST Chemistry Webbook ( 10.18434/T4D303

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