Methoxy radical


Gas phase ion energetics data

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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:
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard

View reactions leading to CH3O+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)10.72eVN/AN/AL
Quantity Value Units Method Reference Comment
ΔfH(+) ion,0K253.1kcal/molN/AN/A 

Ionization energy determinations

IE (eV) Method Reference Comment
10.72DERRuscic and Berkowitz, 1991LL
8.6DERLias, Bartmess, et al., 1988LL
8.3 ± 0.3CIELGriffiths and Harris, 1987LBLHLM
7.37 ± 0.03PEDyke, 1987LBLHLM

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CHO+8.73H2PIKuo, Zhang, et al., 1994LL

Anion protonation reactions

CH3O- + Hydrogen cation = Methyl Alcohol

By formula: CH3O- + H+ = CH4O

Quantity Value Units Method Reference Comment
Δr382. ± 2.kcal/molAVGN/AAverage of 6 values; Individual data points
Quantity Value Units Method Reference Comment
Δr376.02 ± 0.62kcal/molH-TSNee, Osterwalder, et al., 2006gas phase; B
Δr376.04 ± 0.55kcal/molH-TSOsborn, Leahy, et al., 1998gas phase; B
Δr374.0 ± 2.0kcal/molIMREBartmess, Scott, et al., 1979gas phase; The acidity is 1.2 kcal/mol stronger than that from the D-EA cycle, due to the multi-compound fit for the acidity scale.; value altered from reference due to change in acidity scale; B
Δr374.6 ± 2.1kcal/molH-TSHaas and Harrison, 1993gas phase; Both metastable and 50 eV collision energy.; B
Δr375.10 ± 0.60kcal/molTDEqMeot-ner and Sieck, 1986gas phase; Experimental entropy: 21.5 eu, 0.6 less than H2O; B

Vibrational and/or electronic energy levels

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

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

Data compiled by: Marilyn E. Jacox

State:   A


 Energy 
 (cm-1
 Med.   Transition   λmin 
 (nm) 
 λmax 
 (nm) 
 References

To = 31644.2 gas A-X 271 421 Style and Ward, 1953
Ohbayashi, Akimoto, et al., 1977
Wendt and Hunziker, 1979
Inoue, Akimoto, et al., 1980
Powers, Hopkins, et al., 1981
Carrick, Brossard, et al., 1985
Brossard, Carrick, et al., 1986
Garland, 1988
Foster, Misra, et al., 1988
Liu, Damo, et al., 1989
Kappert and Temps, 1989
Liu, Foster, et al., 1990
Lee, Wann, et al., 1993
Geers, Kappert, et al., 1994
Osborn, Leahy, et al., 1995
Powers, Pushkarsky, et al., 1997
Liu, Chen, et al., 2009
To = 31291 ± 3 Ar A-X 270 420 Chiang, Hsu, et al., 1989


Vib. 
sym. 
 No.   Approximate 
 type of mode 
 cm-1   Med.   Method   References

a1 1 CH3 stretch 2947.8 gas LF Powers, Pushkarsky, et al., 1997
2 Umbrella 1289.3 gas LF Foster, Misra, et al., 1988
Lee, Wann, et al., 1993
Powers, Pushkarsky, et al., 1997
2 Umbrella 1308 ± 4 Ar LF Chiang, Hsu, et al., 1989
3 CO stretch 662.4 gas AB EM Wendt and Hunziker, 1979
Brossard, Carrick, et al., 1986
3 CO stretch 662.4 gas LF Foster, Misra, et al., 1988
Powers, Pushkarsky, et al., 1997
3 CO stretch 657 ± 2 Ar LF Chiang, Hsu, et al., 1989
e 4 CH3 stretch 3077.8 T gas LF Powers, Pushkarsky, et al., 1997
5 CH2 scissors 1403.0 gas LF Foster, Misra, et al., 1988
Powers, Pushkarsky, et al., 1997
5 CH2 scissors 1410 ± 3 Ar LF Chiang, Hsu, et al., 1989
6 HCO deform. 929.5 gas LF Powers, Pushkarsky, et al., 1997

State:   X


Vib. 
sym. 
 No.   Approximate 
 type of mode 
 cm-1   Med.   Method   References

a1 1 CH3 stretch 2840 T gas LF Foster, Misra, et al., 1988
Lee, Wann, et al., 1993
2 Umbrella 1376 gas SEP TPE Temps, 1995
Nee, Osterwalder, et al., 2006
3 CO stretch 1047 gas LF EM Inoue, Akimoto, et al., 1980
Ebata, Yanagishita, et al., 1982
Brossard, Carrick, et al., 1986
Foster, Misra, et al., 1988
Lee, Wann, et al., 1993
Temps, 1995
3 CO stretch 1044 ± 2 Ar LF Chiang, Hsu, et al., 1989
e 4 CH3 stretch (E) 2955 gas TPE Nee, Osterwalder, et al., 2006
4 CH3 str. (E1/2) 2885 T gas LD Han, Utkin, et al., 2002
Han, Hu, et al., 2007
4 CH3 stretch 2778 gas SEP Temps, 1995
4 CH3 stretch 2758 ± 3 Ar LF Chiang, Hsu, et al., 1989
5 CH2 scissors(E) 1519 gas PE TPE Osborn, Leahy, et al., 1998, 2
Ramond, Davico, et al., 2000
Nee, Osterwalder, et al., 2006
5 CH2 scissor(A1) 1412 ± 4 T gas LF Lee, Wann, et al., 1993
5 CH2 scissor(A1) 1406 ± 2 T Ar LF Chiang, Hsu, et al., 1989
6 HCO deform. (E) 1233 gas PE TPE Osborn, Leahy, et al., 1998, 2
Ramond, Davico, et al., 2000
Nee, Osterwalder, et al., 2006
6 HCO deform.(A1) 651.5 gas LF SEP Foster, Misra, et al., 1988
Geers, Kappert, et al., 1993
Lee, Wann, et al., 1993
Temps, 1995
6 HCO deform.(A1) 651.5 gas PE Osborn, Leahy, et al., 1998, 2
Ramond, Davico, et al., 2000

Additional references: Jacox, 1994, page 236; Jacox, 1998, page 271; Jacox, 2003, page 257; Radford and Russell, 1977; Inoue, Akimoto, et al., 1979; Russell and Radford, 1980; Endo, Saito, et al., 1984; Fuke, Ozawa, et al., 1986; Agrawalla and Setser, 1986; Wantuck, Oldenborg, et al., 1987; Lin, Lee, et al., 1988; Momose, Endo, et al., 1988; Suto, Ye, et al., 1988; Geers, Kappert, et al., 1990; Powers, Pushkarsky, et al., 1997, 2; Applegate, Pushkarsky, et al., 1999; Liu, Chen, et al., 2009, 2

Notes

TTentative assignment or approximate value
oEnergy separation between the v = 0 levels of the excited and electronic ground states.

References

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, Notes

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

Ruscic and Berkowitz, 1991
Ruscic, B.; Berkowitz, J., Photoionization mass spectrometric studies of the isomeric transient species CD2OH and CD3O, J. Chem. Phys., 1991, 95, 4033. [all data]

Lias, Bartmess, et al., 1988
Lias, S.G.; Bartmess, J.E.; Liebman, J.F.; Holmes, J.L.; Levin, R.D.; Mallard, W.G., Gas-phase ion and neutral thermochemistry, J. Phys. Chem. Ref. Data, Suppl. 1, 1988, 17, 1-861. [all data]

Griffiths and Harris, 1987
Griffiths, W.J.; Harris, F.M., Ionization energies of CH3O and CH3S radicals measured by charge-inversion energy-loss spectrometry, Chem. Phys. Lett., 1987, 142, 7. [all data]

Dyke, 1987
Dyke, J.M., Properties of gas-phase ions, J. Chem. Soc. Faraday Trans., 1987, 83, 69. [all data]

Kuo, Zhang, et al., 1994
Kuo, S.-C.; Zhang, Z.; Klemm, R.B.; Liebman, J.F.; Stief, L.J.; Nesbitt, F.L., Photoionization of hydroxymethyl (CD2OH and CD3O) radicals: Photoion efficiency spectra, ionization energies and thermochemistry, J. Phys. Chem., 1994, 98, 4026. [all data]

Nee, Osterwalder, et al., 2006
Nee, M.J.; Osterwalder, A.; Zhou, J.; Neumark, D.M., Slow electron velocity-map imaging photoelectron spectra of the methoxide anion, J. Chem. Phys., 2006, 125, 1, 014306, https://doi.org/10.1063/1.2212411 . [all data]

Osborn, Leahy, et al., 1998
Osborn, D.L.; Leahy, D.J.; Kim, E.H.; deBeer, E.; Neumark, D.M., Photoelectron spectroscopy of CH3O- and CD3O-, Chem. Phys. Lett., 1998, 292, 4-6, 651-655, https://doi.org/10.1016/S0009-2614(98)00717-9 . [all data]

Bartmess, Scott, et al., 1979
Bartmess, J.E.; Scott, J.A.; McIver, R.T., Jr., The gas phase acidity scale from methanol to phenol, J. Am. Chem. Soc., 1979, 101, 6047. [all data]

Haas and Harrison, 1993
Haas, M.J.; Harrison, A.G., The Fragmentation of Proton-Bound Cluster Ions and the Gas-Phase Acidities of Alcohols, Int. J. Mass Spectrom. Ion Proc., 1993, 124, 2, 115, https://doi.org/10.1016/0168-1176(93)80003-W . [all data]

Meot-ner and Sieck, 1986
Meot-ner, M.; Sieck, L.W., Relative acidities of water and methanol, and the stabilities of the dimer adducts, J. Phys. Chem., 1986, 90, 6687. [all data]

Style and Ward, 1953
Style, D.W.G.; Ward, J.C., Fluorescent spectra from ethyl nitrate. Part 1.?Supposed emissions from alkoxy radicals and NO2, Trans. Faraday Soc., 1953, 49, 999, https://doi.org/10.1039/tf9534900999 . [all data]

Ohbayashi, Akimoto, et al., 1977
Ohbayashi, K.; Akimoto, H.; Tanaka, I., Emission spectra of methoxyl, ethoxyl, and isopropoxyl radicals, J. Phys. Chem., 1977, 81, 8, 798, https://doi.org/10.1021/j100523a023 . [all data]

Wendt and Hunziker, 1979
Wendt, H.R.; Hunziker, H.E., Electronic absorption spectrum of CH3O, J. Chem. Phys., 1979, 71, 12, 5202, https://doi.org/10.1063/1.438296 . [all data]

Inoue, Akimoto, et al., 1980
Inoue, G.; Akimoto, H.; Okuda, M., Spectroscopy of the CH3O A 2A1--X 2E system by laser-excited fluorescence method, J. Chem. Phys., 1980, 72, 3, 1769, https://doi.org/10.1063/1.439291 . [all data]

Powers, Hopkins, et al., 1981
Powers, E.; Hopkins, J.B.; Smalley, R.E., Laser production of jet-cooled radicals. Methoxy and methoxy-argon, J. Phys. Chem., 1981, 85, 19, 2711, https://doi.org/10.1021/j150619a003 . [all data]

Carrick, Brossard, et al., 1985
Carrick, P.G.; Brossard, S.D.; Engelking, P.C., Experimental observation of the spin-orbit splitting in methoxy, J. Chem. Phys., 1985, 83, 4, 1995, https://doi.org/10.1063/1.449338 . [all data]

Brossard, Carrick, et al., 1986
Brossard, S.D.; Carrick, P.G.; Chappell, E.L.; Hulegaard, S.C.; Engelking, P.C., The 2A1--2E electronic spectrum of methoxy, CH3O: Vibrational progressions, and spin-orbit and Jahn--Teller couplings, J. Chem. Phys., 1986, 84, 5, 2459, https://doi.org/10.1063/1.450364 . [all data]

Garland, 1988
Garland, N.L., and D. R. Crosley, 1988, J. Phys. Chem. 92, 5322. [all data]

Foster, Misra, et al., 1988
Foster, S.C.; Misra, P.; Lin, T.-Y.; Damo, C.P.; Carter, C.C.; Miller, T.A., Free jet-cooled laser-induced fluorescence spectrum of methoxy. 1. Vibronic analysis of the ~A and ~X states, J. Phys. Chem., 1988, 92, 21, 5914, https://doi.org/10.1021/j100332a014 . [all data]

Liu, Damo, et al., 1989
Liu, X.; Damo, C.P.; Lin, T.-Y.D.; Foster, S.C.; Misra, P.; Yu, L.; Miller, T.A., Free jet-cooled laser-induced fluorescence spectrum of methoxy radical. 2. Rotational analysis of the ~A2A1 .tautm. ~X2E electronic transition, J. Phys. Chem., 1989, 93, 6, 2266, https://doi.org/10.1021/j100343a016 . [all data]

Kappert and Temps, 1989
Kappert, J.; Temps, F., Rotationally resolved laser-induced fluorescence excitation studies of CH3O, Chem. Phys., 1989, 132, 1-2, 197, https://doi.org/10.1016/0301-0104(89)80088-6 . [all data]

Liu, Foster, et al., 1990
Liu, X.; Foster, S.C.; Williamson, J.M.; Yu, L.; Miller, T.A., The spin-rotation interactions in the methoxy radical, Mol. Phys., 1990, 69, 2, 357, https://doi.org/10.1080/00268979000100251 . [all data]

Lee, Wann, et al., 1993
Lee, Y.-Y.; Wann, G.-H.; Lee, Y.-P., Vibronic analysis of the A→X laser-induced fluorescence of jet-cooled methoxy (CH3O) radical, J. Chem. Phys., 1993, 99, 12, 9465, https://doi.org/10.1063/1.465481 . [all data]

Geers, Kappert, et al., 1994
Geers, A.; Kappert, J.; Temps, F.; Wiebrecht, J.W., Rotation--vibration state resolved unimolecular dynamics of highly vibrationally excited CH3O (X 2E). I. Observed stimulated emission pumping spectra, J. Chem. Phys., 1994, 101, 5, 3618, https://doi.org/10.1063/1.467547 . [all data]

Osborn, Leahy, et al., 1995
Osborn, D.L.; Leahy, D.J.; Ross, E.M.; Neumark, D.M., Study of the predissociation of by fast beam photofragment translational spectroscopy, Chem. Phys. Lett., 1995, 235, 5-6, 484, https://doi.org/10.1016/0009-2614(95)00151-S . [all data]

Powers, Pushkarsky, et al., 1997
Powers, D.E.; Pushkarsky, M.B.; Miller, T.A., Rovibronic analysis of the laser induced fluorescence excitation spectrum of the jet-cooled methoxy radical, J. Chem. Phys., 1997, 106, 17, 6863, https://doi.org/10.1063/1.473712 . [all data]

Liu, Chen, et al., 2009
Liu, J.; Chen, M.-W.; Melnik, D.; Yi, J.T.; Miller, T.A., The spectroscopic characterization of the methoxy radical. I. Rotationally resolved A [sup 2]A[sub 1]--X [sup 2]E electronic spectra of CH[sub 3]O, J. Chem. Phys., 2009, 130, 7, 074302, https://doi.org/10.1063/1.3072104 . [all data]

Chiang, Hsu, et al., 1989
Chiang, S.-Y.; Hsu, Y.-C.; Lee, Y.-P., Laser-induced emission of CH3O in solid argon, J. Chem. Phys., 1989, 90, 1, 81, https://doi.org/10.1063/1.456471 . [all data]

Temps, 1995
Temps, F., VIBRATIONAL SPECTROSCOPY, INTRAMOLECULAR DYNAMICS AND STATE SPECIFIC UNIMOLECULAR DISSOCIATION OF, Adv. Ser. Phys. Chem., 1995, 4, 375. [all data]

Ebata, Yanagishita, et al., 1982
Ebata, T.; Yanagishita, H.; Obi, K.; Tanaka, I., Ã→X fluorescence spectra of CH3O and C2H5O generated by the Arf laser photolysis of alkyl nitrites, Chem. Phys., 1982, 69, 1-2, 27, https://doi.org/10.1016/0301-0104(82)88129-9 . [all data]

Han, Utkin, et al., 2002
Han, J.-X.; Utkin, Yu.G.; Chen, H.-B.; Burns, L.A.; Curl, R.F., High-resolution infrared spectra of the C-H asymmetric stretch vibration of jet-cooled methoxy radical (CH[sub 3]O), J. Chem. Phys., 2002, 117, 14, 6538, https://doi.org/10.1063/1.1507116 . [all data]

Han, Hu, et al., 2007
Han, J.; Hu, S.; Chen, H.; Utkin, Y.; Brown, J.M.; Curl, R.F., Jet-cooled infrared spectrum of methoxy in the CH stretching region, Phys. Chem. Chem. Phys., 2007, 9, 28, 3725, https://doi.org/10.1039/b700502d . [all data]

Osborn, Leahy, et al., 1998, 2
Osborn, D.L.; Leahy, D.J.; Kim, E.H.; de Beer, E.; Neumark, D.M., Photoelectron spectroscopy of CH3O- and CD3O-, Chem. Phys. Lett., 1998, 292, 4-6, 651, https://doi.org/10.1016/S0009-2614(98)00717-9 . [all data]

Ramond, Davico, et al., 2000
Ramond, T.M.; Davico, G.E.; Schwartz, R.L.; Lineberger, W.C., Vibronic structure of alkoxy radicals via photoelectron spectroscopy, J. Chem. Phys., 2000, 112, 3, 1158, https://doi.org/10.1063/1.480767 . [all data]

Geers, Kappert, et al., 1993
Geers, A.; Kappert, J.; Temps, F.; Sears, T.J., Stimulated emission pumping spectroscopy of CH3O (X 2E, ν6): New observations on the Jahn--Teller effect, J. Chem. Phys., 1993, 98, 5, 4297, https://doi.org/10.1063/1.465036 . [all data]

Jacox, 1994
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules, American Chemical Society, Washington, DC, 1994, 464. [all data]

Jacox, 1998
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules: supplement A, J. Phys. Chem. Ref. Data, 1998, 27, 2, 115-393, https://doi.org/10.1063/1.556017 . [all data]

Jacox, 2003
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules: supplement B, J. Phys. Chem. Ref. Data, 2003, 32, 1, 1-441, https://doi.org/10.1063/1.1497629 . [all data]

Radford and Russell, 1977
Radford, H.E.; Russell, D.K., Spectroscopic detection of methoxy (CH3O), J. Chem. Phys., 1977, 66, 5, 2222, https://doi.org/10.1063/1.434142 . [all data]

Inoue, Akimoto, et al., 1979
Inoue, G.; Akimoto, H.; Okuda, M., Laser-induced fluorescence spectra of CH3O, Chem. Phys. Lett., 1979, 63, 2, 213, https://doi.org/10.1016/0009-2614(79)87002-5 . [all data]

Russell and Radford, 1980
Russell, D.K.; Radford, H.E., Analysis of the LMR spectra of methoxy, CH3O, J. Chem. Phys., 1980, 72, 4, 2750, https://doi.org/10.1063/1.439423 . [all data]

Endo, Saito, et al., 1984
Endo, Y.; Saito, S.; Hirota, E., The microwave spectrum of the methoxy radical CH3O, J. Chem. Phys., 1984, 81, 1, 122, https://doi.org/10.1063/1.447375 . [all data]

Fuke, Ozawa, et al., 1986
Fuke, K.; Ozawa, K.; Kaya, K., Electronic spectra and predissociation of jet-cooled CH3O and CH3O-Ar in the Ã2A1 state, Chem. Phys. Lett., 1986, 126, 2, 119, https://doi.org/10.1016/S0009-2614(86)80023-9 . [all data]

Agrawalla and Setser, 1986
Agrawalla, B.S.; Setser, D.W., Infrared chemiluminescence and laser-induced fluorescence studies of energy disposal by reactions of fluorine and chlorine atoms with hydrogen sulfide, deuterium sulfide, hydrogen selenide, water, water-d2, and methanol, J. Phys. Chem., 1986, 90, 11, 2450, https://doi.org/10.1021/j100402a039 . [all data]

Wantuck, Oldenborg, et al., 1987
Wantuck, P.J.; Oldenborg, R.C.; Baughcum, S.L.; Winn, K.R., Collisional quenching of methoxy(A2A1) radical, J. Phys. Chem., 1987, 91, 12, 3253, https://doi.org/10.1021/j100296a030 . [all data]

Lin, Lee, et al., 1988
Lin, S.-R.; Lee, Y.-P.; Nee, J.B., Radiative lifetime and quenching of the A 2A1 state of the CH3O radical, J. Chem. Phys., 1988, 88, 1, 171, https://doi.org/10.1063/1.454633 . [all data]

Momose, Endo, et al., 1988
Momose, T.; Endo, Y.; Hirota, E.; Shida, T., The submillimeter-wave spectrum of the 13CH3O radical, J. Chem. Phys., 1988, 88, 9, 5338, https://doi.org/10.1063/1.454593 . [all data]

Suto, Ye, et al., 1988
Suto, M.; Ye, C.; Lee, L.C., CH3O(A--X) fluorescence from photodissociation of dimethyl ether, J. Chem. Phys., 1988, 89, 10, 6555, https://doi.org/10.1063/1.455378 . [all data]

Geers, Kappert, et al., 1990
Geers, A.; Kappert, J.; Temps, F.; Wiebrecht, J.W., Stimulated-emission pumping spectroscopy of highly excited states of CH_3O (X~ ^2E): zero-order vibrational states at 3000 cm^-1 ≤ 9000 cm^-1, J. Opt. Soc. Am. B, 1990, 7, 9, 1935, https://doi.org/10.1364/JOSAB.7.001935 . [all data]

Powers, Pushkarsky, et al., 1997, 2
Powers, D.E.; Pushkarsky, M.B.; Miller, T.A., Vibrational mode and frequency dependence of the photofragmentation of the methoxy radical, J. Chem. Phys., 1997, 106, 17, 6878, https://doi.org/10.1063/1.473713 . [all data]

Applegate, Pushkarsky, et al., 1999
Applegate, B.E.; Pushkarsky, M.B.; Miller, T.A., Spectral Analysis and Photofragmentation Dynamics of the Perdeuteromethoxy Radical, J. Phys. Chem. A, 1999, 103, 11, 1538, https://doi.org/10.1021/jp984141n . [all data]

Liu, Chen, et al., 2009, 2
Liu, J.; Chen, M.-W.; Melnik, D.; Miller, T.A.; Endo, Y.; Hirota, E., The spectroscopic characterization of the methoxy radical. II. Rotationally resolved A [sup 2]A[sub 1]-X [sup 2]E electronic and X [sup 2]E microwave spectra of the perdeuteromethoxy radical CD[sub 3]O, J. Chem. Phys., 2009, 130, 7, 074303, https://doi.org/10.1063/1.3072105 . [all data]


Notes

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, References