Home Symbol which looks like a small house Up Solid circle with an upward pointer in it

Methane

Data at NIST subscription sites:

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.


Gas phase ion energetics data

Go To: Top, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data evaluated as indicated in comments:
HL - E.P. Hunter and S.G. Lias
L - S.G. Lias

Data compiled as indicated in comments:
B - J.E. Bartmess
LBLHLM - S.G. Lias, J.E. Bartmess, J.F. Liebman, J.L. Holmes, R.D. Levin, and W.G. Mallard
LLK - S.G. Lias, R.D. Levin, and S.A. Kafafi
RDSH - H.M. Rosenstock, K. Draxl, B.W. Steiner, and J.T. Herron

View reactions leading to CH4+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)12.61 ± 0.01eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)543.5kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity520.6kJ/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
12.61 ± 0.01PIBerkowitz, Greene, et al., 1987LBLHLM
12.6 ± 0.4EIChatham, Hils, et al., 1984LBLHLM
12.63 ± 0.02EIPlessis, Marmet, et al., 1983LBLHLM
13.6PEKimura, Katsumata, et al., 1981LLK
12.75 ± 0.02PEBieri, Burger, et al., 1977LLK
12.82 ± 0.02EISelim and El-Kholy, 1975LLK
12.6PEDebies and Rabalais, 1975LLK
12.6PIRabalais, Debies, et al., 1974LLK
12.8EIMorrison and Traeger, 1973LLK
12.64PEPotts and Price, 1972LLK
12.94 ± 0.04EIFinney and Harrison, 1972LLK
12.51PEBergmark, Rabalais, et al., 1972LLK
~12.51PERabalais, Bergmark, et al., 1971LLK
<=12.615 ± 0.010PIChupka and Berkowitz, 1971LLK
12.78PEPullen, Carlson, et al., 1970RDSH
12.75PEBrundle, Robin, et al., 1970RDSH
<=12.70EILossing and Semeluk, 1969RDSH
12.99 ± 0.05EIWilliams and Hamill, 1968RDSH
12.75 ± 0.05TEVillarejo, Stockbauer, et al., 1968RDSH
12.9CICermak, 1968RDSH
12.70PEBaker, Baker, et al., 1968RDSH
12.55 ± 0.05PIBrehm, 1966RDSH
12.704 ± 0.008PINicholson, 1965RDSH
12.71 ± 0.02PIDibeler, Krauss, et al., 1965RDSH
13.00 ± 0.02EIMelton and Hamill, 1964RDSH
13.6PEBieri and Asbrink, 1980Vertical value; LLK
13.6 ± 0.1PEBieri, Burger, et al., 1977Vertical value; LLK
13.60EIHarshbarger, Robin, et al., 1973Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
C+25. ± 2.?EIChatham, Hils, et al., 1984LBLHLM
C+19.56 ± 0.202H2EIPlessis, Marmet, et al., 1983LBLHLM
C+<=25.2?EIMorrison and Traeger, 1973LLK
CH+22.2 ± 0.4?EIChatham, Hils, et al., 1984LBLHLM
CH+19.11 ± 0.20H-+H2EIPlessis, Marmet, et al., 1983LBLHLM
CH+19.87 ± 0.20H+H2EIPlessis, Marmet, et al., 1983LBLHLM
CH+22.4H2+H?EIMorrison and Traeger, 1973LLK
CH2+15.1 ± 0.4H2EIChatham, Hils, et al., 1984LBLHLM
CH2+15.06 ± 0.02H2EIPlessis, Marmet, et al., 1983LBLHLM
CH2+15.16 ± 0.02H2PIMcCulloh and Dibeler, 1976T = 0K; LLK
CH2+15.3H2EIMorrison and Traeger, 1973LLK
CH2+15.19 ± 0.02H2PIChupka, 1968RDSH
CH2+15.16 ± 0.04H2PIDibeler, Krauss, et al., 1965RDSH
CH3+14.3 ± 0.4HEIChatham, Hils, et al., 1984LBLHLM
CH3+13.25 ± 0.08H-EIPlessis, Marmet, et al., 1983LBLHLM
CH3+14.01 ± 0.08HEIPlessis, Marmet, et al., 1983LBLHLM
CH3+14.30HPIPECOStockbauer, 1977LLK
CH3+14.324 ± 0.003HPIMcCulloh and Dibeler, 1976T = 0K; LLK
CH3+14.4HEIMorrison and Traeger, 1973LLK
CH3+14.30HEILossing and Semeluk, 1970RDSH
CH3+14.24 ± 0.05HEIWilliams and Hamill, 1968RDSH
CH3+13.50 ± 0.05H-PIChupka, 1968RDSH
CH3+14.320 ± 0.004HPIChupka, 1968RDSH
CH3+14.23 ± 0.05HPIBrehm, 1966RDSH
CH3+14.25 ± 0.02HPIDibeler, Krauss, et al., 1965RDSH
H+21.3 ± 0.3CH3EILocht, Olivier, et al., 1979LLK
H+24.0 ± 0.5CH3EIAppell and Kubach, 1971LLK

De-protonation reactions

CH3- + Hydrogen cation = Methane

By formula: CH3- + H+ = CH4

Quantity Value Units Method Reference Comment
Deltar1743.6 ± 2.9kJ/molD-EAEllison, Engelking, et al., 1978gas phase; B
Deltar1749. ± 15.kJ/molCIDTGraul and Squires, 1990gas phase; B
Deltar>1691.1 ± 0.42kJ/molG+TSBohme, Lee-Ruff, et al., 1972gas phase; B
Deltar1735.5kJ/molN/ACheck, Faust, et al., 2001gas phase; FeBr3; ; «DELTA»S(EA)=9.3; B
Quantity Value Units Method Reference Comment
Deltar1709.8 ± 3.3kJ/molH-TSEllison, Engelking, et al., 1978gas phase; B
Deltar1715. ± 15.kJ/molH-TSGraul and Squires, 1990gas phase; B
Deltar>1657.3kJ/molIMRBBohme, Lee-Ruff, et al., 1972gas phase; B
Deltar1704.1kJ/molN/ACheck, Faust, et al., 2001gas phase; FeBr3; ; «DELTA»S(EA)=9.3; B

References

Go To: Top, Gas phase ion energetics data, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Berkowitz, Greene, et al., 1987
Berkowitz, J.; Greene, J.P.; Cho, H.; Ruscic, B., The ionization potentials of CH4 and CD4, J. Chem. Phys., 1987, 86, 674. [all data]

Chatham, Hils, et al., 1984
Chatham, H.; Hils, D.; Robertson, R.; Gallagher, A., Total and partial electron collisional ionization cross sections for CH4, C2H6, SiH4, and Si2H6, J. Chem. Phys., 1984, 81, 1770. [all data]

Plessis, Marmet, et al., 1983
Plessis, P.; Marmet, P.; Dutil, R., Ionization and appearance potentials of CH4 by electron impact, J. Phys. B:, 1983, 16, 1283. [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Bieri, Burger, et al., 1977
Bieri, G.; Burger, F.; Heilbronner, E.; Maier, J.P., Valence ionization enrgies of hydrocarbons, Helv. Chim. Acta, 1977, 60, 2213. [all data]

Selim and El-Kholy, 1975
Selim, E.T.M.; El-Kholy, S.B., Mass spectrometric ionization and dissociation of methane, Indian J. Pure Appl. Phys., 1975, 13, 233. [all data]

Debies and Rabalais, 1975
Debies, T.P.; Rabalais, J.W., Calculated photoionization cross-sections and angular distributions for the isoelectronic series Ne, HF, H2O, NH3, and CH4, J. Am. Chem. Soc., 1975, 97, 487. [all data]

Rabalais, Debies, et al., 1974
Rabalais, J.W.; Debies, T.P.; Berkosky, J.L.; Huang, J.-T.J.; Ellison, F.O., Calculated photoionization cross sections relative experimental photoionization intensities for a selection of small molecules, J. Chem. Phys., 1974, 61, 516. [all data]

Morrison and Traeger, 1973
Morrison, J.D.; Traeger, J.C., Ionization and dissociation by electron impact. III. CH4 and SiH4, Int. J. Mass Spectrom. Ion Phys., 1973, 11, 289. [all data]

Potts and Price, 1972
Potts, A.W.; Price, W.C., The photoelectron spectra of methane, silane germane and stannane, Proc. R. Soc. London A:, 1972, 165. [all data]

Finney and Harrison, 1972
Finney, C.D.; Harrison, A.G., A third-derivative method for determining electron-impact onset potentials, Int. J. Mass Spectrom. Ion Phys., 1972, 9, 221. [all data]

Bergmark, Rabalais, et al., 1972
Bergmark, T.; Rabalais, J.W.; Werme, L.O.; Karlsson, L.; Siegbahn, K., High-resolution electron spectra of methane, thiophene, 2-bromothiphene, and 3-bromothiophene in Electron Spectroscopy, ed. D.A. Shirley (North-Holland Pub. Co., Amsterdam), 1972. [all data]

Rabalais, Bergmark, et al., 1971
Rabalais, J.W.; Bergmark, T.; Werme, L.O.; Karlsson, L.; Siegbahn, K., The Jahn-Teller effect in the electron spectrum of methane, Phys. Scr., 1971, 3, 13. [all data]

Chupka and Berkowitz, 1971
Chupka, W.A.; Berkowitz, J., Photoionization of methane: ionization potential and proton affinity of CH4, J. Chem. Phys., 1971, 54, 4256. [all data]

Pullen, Carlson, et al., 1970
Pullen, B.P.; Carlson, T.A.; Moddeman, W.E.; Schweitzer, G.K.; Bull, W.E., Photoelectron spectra of methane, silane, germane, methyl fluoride, difluoromethane, and trifluoromethane, J. Chem. Phys., 1970, 53, 768. [all data]

Brundle, Robin, et al., 1970
Brundle, C.R.; Robin, M.B.; Basch, H., Electronic energies and electronic structures of the fluoromethanes, J. Chem. Phys., 1970, 53, 2196. [all data]

Lossing and Semeluk, 1969
Lossing, F.P.; Semeluk, G.P., Threshold ionization efficiency curves for monoenergetic electron impact on H2, D2, CH4 and CD4, Intern. J. Mass Spectrom. Ion Phys., 1969, 2, 408. [all data]

Williams and Hamill, 1968
Williams, J.M.; Hamill, W.H., Ionization potentials of molecules and free radicals and appearance potentials by electron impact in the mass spectrometer, J. Chem. Phys., 1968, 49, 4467. [all data]

Villarejo, Stockbauer, et al., 1968
Villarejo, D.; Stockbauer, R.; Inghram, M.G., Measurement of threshold electrons in the photoionization of small molecules, Bull. Am. Phys. Soc., 1968, 13, 39. [all data]

Cermak, 1968
Cermak, V., Penning ionization electron spectroscopy. I. Determination of ionization potentials of polyatomic molecules, Collection Czech. Chem. Commun., 1968, 33, 2739. [all data]

Baker, Baker, et al., 1968
Baker, A.D.; Baker, C.; Brundle, C.R.; Turner, D.W., The electronic structures of methane, ethane, ethylene and formaldehyde studied by high-resolution molecular photoelectron spectroscopy, Intern. J. Mass Spectrom. Ion Phys., 1968, 1, 285. [all data]

Brehm, 1966
Brehm, B., Massenspektrometrische Untersuchung der Photoionisation von Molekulen, Z. Naturforsch., 1966, 21a, 196. [all data]

Nicholson, 1965
Nicholson, A.J.C., Photoionization-efficiency curves. II. False and genuine structure, J. Chem. Phys., 1965, 43, 1171. [all data]

Dibeler, Krauss, et al., 1965
Dibeler, V.H.; Krauss, M.; Reese, R.M.; Harllee, F.N., Mass-spectrometric study of photoionization. III. Methane and methane-d4, J. Chem. Phys., 1965, 42, 3791. [all data]

Melton and Hamill, 1964
Melton, C.E.; Hamill, W.H., Appearance potentials by the retarding potential-difference method for secondary ions produced by excited-neutral, excited ion-neutral, and ion-neutral reactions, J. Chem. Phys., 1964, 41, 1469. [all data]

Bieri and Asbrink, 1980
Bieri, G.; Asbrink, L., 30.4-nm He(II) photoelectron spectra of organic molecules, J. Electron Spectrosc. Relat. Phenom., 1980, 20, 149. [all data]

Harshbarger, Robin, et al., 1973
Harshbarger, W.R.; Robin, M.B.; Lassettre, E.N., The electron impact spectra of the fluoromethanes, J. Electron Spectrosc. Relat. Phenom., 1973, 1, 319. [all data]

McCulloh and Dibeler, 1976
McCulloh, K.E.; Dibeler, V.H., Enthalpy of formation of methyl and methylene radicals of photoionization studies of methane and ketene, J. Chem. Phys., 1976, 64, 4445. [all data]

Chupka, 1968
Chupka, W.A., Mass-spectrometric study of the photoionization of methane, J. Chem. Phys., 1968, 48, 2337. [all data]

Stockbauer, 1977
Stockbauer, R., A threshold photoelectron-photoion coincidence mass spectrometer for measureing ion kinetic energy release on fragmentation, Int. J. Mass Spectrom. Ion Processes, 1977, 25, 89. [all data]

Lossing and Semeluk, 1970
Lossing, F.P.; Semeluk, G.P., Free radicals by mass spectrometry. XLII.Ionization potentials and ionic heats of formation for C1-C4 alkyl radicals, Can. J. Chem., 1970, 48, 955. [all data]

Locht, Olivier, et al., 1979
Locht, R.; Olivier, J.L.; Momigny, J., Dissociative autoionization as a mechanism for the proton formation from methane and methane-d4 by low energy electron impact, Chem. Phys., 1979, 43, 425. [all data]

Appell and Kubach, 1971
Appell, J.; Kubach, C., On the formation of energetic protons by electron impact on methane, Chem. Phys. Lett., 1971, 11, 486. [all data]

Ellison, Engelking, et al., 1978
Ellison, G.B.; Engelking, P.C.; Lineberger, W.C., An experimental determination of the geometry and electron affinity of CH3, J. Am. Chem. Soc., 1978, 100, 2556. [all data]

Graul and Squires, 1990
Graul, S.T.; Squires, R.R., Gas-Phase Acidities Derived from Threshold Energies for Activated Reactions, J. Am. Chem. Soc., 1990, 112, 7, 2517, https://doi.org/10.1021/ja00163a007 . [all data]

Bohme, Lee-Ruff, et al., 1972
Bohme, D.K.; Lee-Ruff, E.; Young, L.B., Acidity order of selected bronsted acids in the gas phase at 300K, J. Am. Chem. Soc., 1972, 94, 5153. [all data]

Check, Faust, et al., 2001
Check, C.E.; Faust, T.O.; Bailey, J.M.; Wright, B.J.; Gilbert, T.M.; Sunderlin, L.S., Addition of Polarization and Diffuse Functions to the LANL2DZ Basis Set for P-Block Elements, J. Phys. Chem. A,, 2001, 105, 34, 8111, https://doi.org/10.1021/jp011945l . [all data]


Notes

Go To: Top, Gas phase ion energetics data, References