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

Listing of experimental data for Li2 (Lithium diatomic)

Other names
Lithium; Lithium dimer; dilithium;
INChI SMILES IUPAC name
InChI=1/2Li [Li][Li] dilithium
State Conformation
1Σg C*V
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 215.90 3.00 kJ mol-1 JANAF
Hfg(0K) enthalpy of formation 215.49 3.00 kJ mol-1 JANAF
Entropy (298.15K) entropy 197.00 0.03 J K-1 mol-1 JANAF
Integrated Heat Capacity (0 to 298.15K) integrated heat capacity 9.68   kJ mol-1 JANAF
Heat Capacity (298.15K) heat capacity 36.25   J K-1 mol-1 webbook
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 Σg 351 VEEL5      
Detailed diatomic data
ωe ωexe ωeye Be αe ZPE reference
351.4066 2.58324 -0.005832 0.6725297 0.0070461 175.0259 2007Iri:389

vibrational zero-point energy: 175.7 cm-1
Calculated vibrational frequencies for Li2 (Lithium diatomic).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment
  0.67264   1979HUB/HER

Calculated rotational constants for Li2 (Lithium diatomic).

Product of moments of inertia moments of inertia
25.06189amu Å2   4.16169E-39gm cm2

Geometric Data
picture of Lithium 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
rLiLi 2.673   1 2 1979HUB/HER re

Cartesians
Atom x (Å) y (Å) z (Å)
Li1 0.0000 0.0000 0.0000
Li2 0.0000 0.0000 2.6730

Atom - Atom Distances bond lengths
Distances in Å
  Li1 Li2
Li1   2.6730
Li2 2.6730  

Calculated geometries for Li2 (Lithium diatomic).

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

Connectivity
Atom 1 Atom 2
Li1 Li2

Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 1 1979HUB/HER 1Σg

Ionization Energies (eV)
Ionization Energy I.E. unc. vertical I.E. v.I.E. unc. reference
5.113 0.000     webbook

Electron Affinity (eV)
Electron Affinity unc. reference
0.437 0.009 2002Rie/Tsc:231

Dipole, Quadrupole and Polarizability
Electric dipole moment dipole
For a molecule with D∞h symmetry there is no dipole.
Electric quadrupole moment quadrupole
Calculated electric quadrupole moments for Li2 (Lithium diatomic).

References
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squib reference DOI
1979HUB/HER Huber, K.P.; Herzberg, G., Molecular Spectra and Molecular Structure. IV. Constants of Diatomic Molecules,, Van Nostrand Reinhold Co., 1979  
2002Rie/Tsc:231 JC Rienstra-Kiracofe, GS Tschumper, HF Schaefer III, S Nandi, GB Ellison "Atomic and Molecular Electron Affinities: Photoelectron Experiments and Theoretical Computations" Chemical Reviews 2002, 102, 231-282 10.1021/cr990044u
2007Iri:389 KK Irikura "Experimental Vibrational Zero-Point Energies: Diatomic Molecules" J. Phys. Chem. Ref. Data 36(2), 389, 2007 10.1063/1.2436891
JANAF Chase, M.W., Jr.; Davies, C.A.; Downey, J.R., Jr.; Frurip, D.J.; McDonald, R.A.; Syverud, A.N., JANAF Thermochemical Tables (Third Edition), J. Phys. Chem. Ref. Data,Suppl. 1, 1985, 14, 1.  
VEEL5 M.E. Jacox, Vibrational and Electronic Energy Levels of Polyatomic Transient Molecules, J. Phys. Chem.Ref. Data, Monograph 3 (1994) (updated data in NIST Chemistry Webbook - http://webbook.nist.gov/chemistry/  
webbook NIST Chemistry Webbook (http://webbook.nist.gov/chemistry)  

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