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Experimental data for CH (Methylidyne)

22 02 02 11 45
Other names
Methylidyne;
INChI INChIKey SMILES IUPAC name
InChI=1S/CH/h1H VRLIPUYDFBXWCH-UHFFFAOYSA-N [CH]
State Conformation
2Π1/2 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 595.80 0.60 kJ mol-1 2005Rus/Bog:573
Hfg(0K) enthalpy of formation 592.50 0.60 kJ mol-1 2005Rus/Bog:573
Entropy (298.15K) entropy 183.04   J K-1 mol-1 2005Rus/Bog:573
Integrated Heat Capacity (0 to 298.15K) integrated heat capacity 8.63   kJ mol-1 2005Rus/Bog:573
Heat Capacity (298.15K) heat capacity 29.17   J K-1 mol-1 2005Rus/Bog:573
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 2733 2861 2007Iri:389      

Detailed diatomic data
ωe ωexe ωeye Be αe ZPE reference
2860.751 64.4387 0.3634 14.45988 0.53654 1416.074 2007Iri:389

vibrational zero-point energy: 1366.5 cm-1 (from fundamental vibrations)
Calculated vibrational frequencies for CH (Methylidyne).
More spectroscopic constants are available at the NIST Physics Laboratory website:
http://physics.nist.gov/PhysRefData/MolSpec/Diatomic/Html/Tables/CH.html
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment
  14.45988   2007Iri:389

Calculated rotational constants for CH (Methylidyne).
Product of moments of inertia moments of inertia
1.165821amu Å2   1.935922E-40gm cm2
Geometric Data
picture of Methylidyne

Point Group C∞v


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
rCH 1.120   1 2 1979HUB/HER re

Cartesians
Atom x (Å) y (Å) z (Å)
C1 0.0000 0.0000 0.0000
H2 0.0000 0.0000 1.1199

Atom - Atom Distances bond lengths
Distances in Å
  C1 H2
C1   1.1199
H2 1.1199  

Calculated geometries for CH (Methylidyne).

Bond descriptions


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

Connectivity
Atom 1 Atom 2
C1 H2
Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 2 1979HUB/HER 2Π1/2
27.95 2 1979HUB/HER 2Π3/2
5844 4 1979HUB/HER 4Σ-
23189.8 4 1979HUB/HER 2Δ

Ionization Energies (eV)
Ionization Energy I.E. unc. vertical I.E. v.I.E. unc. reference
10.640 0.010     webbook

Electron Affinity (eV)
Electron Affinity unc. reference
1.238 0.008 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 2Π1/2 C∞v True       1.460 1966Phe/Dal:3-4 ± 0.06 C∞v 1 1
2 1 2Π3/2 C∞v True           C∞v 1 1
3 1 4Σ- C∞v True           C∞v 1 1
4 1 2Δ C∞v True           C∞v 1 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 CH (Methylidyne).
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 2Π1/2 C∞v True       C∞v 1 1
2 1 2Π3/2 C∞v True       C∞v 1 1
3 1 4Σ- C∞v True       C∞v 1 1
4 1 2Δ C∞v True       C∞v 1 1

Calculated electric quadrupole moments for CH (Methylidyne).

References
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squib reference DOI
1966Phe/Dal:3-4 DH Phelps, FW Dalby "Experimental Determination of the Electric Dipole Moment of the Ground Electronic State of CH" Phys. Rev. Lett. 16(1), 1966, 3-4 10.1103/PhysRevLett.16.3
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
2005Rus/Bog:573 B Ruscic, JE Boggs, A Burcat, AG Csaszar, J Demaison, R Janoschek, JML Martin, ML Morton, MJ Rossi, JF Stanton, PG Szalay, PR Westmoreland, F Zabel, T Berces "IUPAC Critical Evaluation of Thermochemical Properties of Selected Radicals. Part I" J. Phys. Chem. Ref. Data, Vol. 34, No. 2, 2005, 573 10.1063/1.1724828
2007Iri:389 KK Irikura "Experimental Vibrational Zero-Point Energies: Diatomic Molecules" J. Phys. Chem. Ref. Data 36(2), 389, 2007 10.1063/1.2436891
webbook NIST Chemistry Webbook (http://webbook.nist.gov/chemistry) 10.18434/T4D303

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