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Experimental data for Se2 (Selenium diatomic)

22 02 02 11 45
State Conformation
3Σg 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 141.10 3.00 kJ mol-1 2005Se
Hfg(0K) enthalpy of formation   3.00 kJ mol-1 2005Se
Entropy (298.15K) entropy 247.38 0.40 J K-1 mol-1 2005Se
Heat Capacity (298.15K) heat capacity 41.71 0.20 J K-1 mol-1 2005Se
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 Σg   385 1979HUB/HER      

vibrational zero-point energy:   cm-1 (from fundamental vibrations)
Calculated vibrational frequencies for Se2 (Selenium diatomic).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment
  0.08992 0.08992 1979HUB/HER

Calculated rotational constants for Se2 (Selenium diatomic).
Product of moments of inertia moments of inertia
187.4736amu Å2   3.113122E-38gm cm2
Geometric Data
picture of Selenium 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
rSeSe 2.166 0.001 1 2 1979HUB/HER re

Atom x (Å) y (Å) z (Å)
Se1 0.0000 0.0000 0.0000
Se2 0.0000 0.0000 2.1660

Atom - Atom Distances bond lengths
Distances in Å
  Se1 Se2
Se1   2.1660
Se2 2.1660  

Calculated geometries for Se2 (Selenium diatomic).

Bond descriptions

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

Atom 1 Atom 2
Se1 Se2
Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 1 1979HUB/HER 3Σg
510 2 1979HUB/HER 1Σg+
25980.36 3 1979HUB/HER

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

Electron Affinity (eV)
Electron Affinity unc. reference
1.940 0.070 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 3Σg D∞h True           D∞h 0 1
2 1 1Σg+ 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 Se2 (Selenium 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 3Σg D∞h True       D∞h 0 1
2 1 1Σg+ D∞h True       D∞h 0 1

Calculated electric quadrupole moments for Se2 (Selenium diatomic).

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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 10.1007/978-1-4757-0961-2
2005Se A Olin, B Nolang, G Osadchii, L-O Ohman, E Rosen, "CHEMICAL THERMODYNAMICS OF SELENIUM", OECD Nuclear Energy Agency, Elsevier, 2005  
webbook NIST Chemistry Webbook ( 10.18434/T4D303

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