Methyl radical
- Formula: CH3
- Molecular weight: 15.0345
- IUPAC Standard InChIKey: WCYWZMWISLQXQU-UHFFFAOYSA-N
- CAS Registry Number: 2229-07-4
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript. - Isotopologues:
- Permanent link for this species. Use this link for bookmarking this species for future reference.
- Information on this page:
- Other data available:
- Data at other public NIST sites:
- Options:
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.
Vibrational and/or electronic energy levels
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 compiled by: Marilyn E. Jacox
State: 4f 2E'?
Energy (cm-1) |
Med. | Transition | λmin (nm) |
λmax (nm) |
References | ||
---|---|---|---|---|---|---|---|
To = 72508 | gas | Hudgens, DiGiuseppe, et al., 1983 | |||||
State: 4p 2A2
Energy (cm-1) |
Med. | Transition | λmin (nm) |
λmax (nm) |
References | ||
---|---|---|---|---|---|---|---|
To = 69853.44 ± 0.13 | gas | Black and Powis, 1988 | |||||
State: 3d 2A1'
Energy (cm-1) |
Med. | Transition | λmin (nm) |
λmax (nm) |
References | ||
---|---|---|---|---|---|---|---|
To = 66805 | gas | 3d2A1'-X | 147 | 150 | Herzberg and Shoosmith, 1956 | ||
Herzberg, 1961 | |||||||
Tx | 3d2A1'-X | 150 | 151 | Milligan and Jacox, 1967 | |||
State: 3d 2E
Energy (cm-1) |
Med. | Transition | λmin (nm) |
λmax (nm) |
References | ||
---|---|---|---|---|---|---|---|
To = 66536 | gas | 3d2E''-X | 144 | 150 | Herzberg and Shoosmith, 1956 | ||
Herzberg, 1961 | |||||||
DiGiuseppe, Hudgens, et al., 1982 | |||||||
Vib. sym. |
No. | Approximate type of mode |
cm-1 | Med. | Method | References | |
---|---|---|---|---|---|---|---|
a2 | 2 | OPLA | 1372 | H | gas | AB MPI | Herzberg, 1961 DiGiuseppe, Hudgens, et al., 1982 |
State: 3p 2A2
Energy (cm-1) |
Med. | Transition | λmin (nm) |
λmax (nm) |
References | ||
---|---|---|---|---|---|---|---|
To = 59972 | gas | Hudgens, DiGiuseppe, et al., 1983 | |||||
Heinze, Heberle, et al., 1994 | |||||||
Vib. sym. |
No. | Approximate type of mode |
cm-1 | Med. | Method | References | |
---|---|---|---|---|---|---|---|
a1' | 1 | CH stretch | 2931 | gas | MPI | Hudgens, DiGiuseppe, et al., 1983 Zhang, Zhang, et al., 2005 | |
a2 | 2 | OPLA | 1323 | gas | MPI | Hudgens, DiGiuseppe, et al., 1983 Zhang, Zhang, et al., 2005 | |
e' | 3 | CH stretch | 3087 | gas | MPI | Zhang, Zhang, et al., 2005 Fu, Hu, et al., 2005 | |
4 | Deformation | 1428 | T | gas | MPI | Zhang, Zhang, et al., 2005 | |
State: 3s 2A1'
Energy (cm-1) |
Med. | Transition | λmin (nm) |
λmax (nm) |
References | ||
---|---|---|---|---|---|---|---|
To = 46239 | gas | 3s2A1'-X | 216 | Herzberg and Shoosmith, 1956 | |||
Herzberg, 1961 | |||||||
Callear and Metcalfe, 1976 | |||||||
Westre, Gansberg, et al., 1992 | |||||||
Settersten, Farrow, et al., 2003 | |||||||
Vib. sym. |
No. | Approximate type of mode |
cm-1 | Med. | Method | References | |
---|---|---|---|---|---|---|---|
a1' | 1 | CH stretch | 2040 | T | gas | Ra | Westre, Gansberg, et al., 1992 |
State: X
Additional references: Jacox, 1994, page 125; Jacox, 1998, page 214; Jacox, 2003, page 156; Frye, Sears, et al., 1988; Parker, Wang, et al., 1989; Sears, Frye, et al., 1989; Westre and Kelly, 1989; Miller, Burton, et al., 1989; Fawzy, Sears, et al., 1990; Rudolph, Hall, et al., 1996
Notes
w | Weak |
m | Medium |
vs | Very strong |
H | (1/2)(2ν) |
T | Tentative assignment or approximate value |
o | Energy separation between the v = 0 levels of the excited and electronic ground states. |
x | Energy separation between the band maximum of the excited electronic state and the v = 0 level of the ground state. |
References
Go To: Top, 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.
Hudgens, DiGiuseppe, et al., 1983
Hudgens, J.W.; DiGiuseppe, T.G.; Lin, M.C.,
Two photon resonance enhanced multiphoton ionization spectroscopy and state assignments of the methyl radical,
J. Chem. Phys., 1983, 79, 2, 571, https://doi.org/10.1063/1.445857
. [all data]
Black and Powis, 1988
Black, J.F.; Powis, I.,
Rotational structure and predissociation dynamics of the methyl 4pz(v=0) Rydberg state investigated by resonance enhanced multiphoton ionization spectroscopy,
J. Chem. Phys., 1988, 89, 7, 3986, https://doi.org/10.1063/1.454832
. [all data]
Herzberg and Shoosmith, 1956
Herzberg, G.; Shoosmith, J.,
Absorption spectrum of free CH3 and CD3 radicals,
Can. J. Phys., 1956, 34, 523. [all data]
Herzberg, 1961
Herzberg, G.,
The Bakerian Lecture. The Spectra and Structures of Free Methyl and Free Methylene,
Proc. Roy. Soc. (London) A262, 1961, 262, 1310, 291, https://doi.org/10.1098/rspa.1961.0120
. [all data]
Milligan and Jacox, 1967
Milligan, D.E.; Jacox, M.E.,
Infrared and Ultraviolet Spectroscopic Study of the Products of the Vacuum-Ultraviolet Photolysis of Methane in Ar and N2 Matrices. The Infrared Spectrum of the Free Radical CH3,
J. Chem. Phys., 1967, 47, 12, 5146, https://doi.org/10.1063/1.1701772
. [all data]
DiGiuseppe, Hudgens, et al., 1982
DiGiuseppe, T.G.; Hudgens, J.W.; Lin, M.C.,
Multiphoton ionization of methyl radicals in the gas phase,
J. Phys. Chem., 1982, 86, 1, 36, https://doi.org/10.1021/j100390a008
. [all data]
Heinze, Heberle, et al., 1994
Heinze, J.; Heberle, N.; Kohse-Hoinghaus, K.,
The CH3 3pz2A2´´ ← X 2A2´´ 000 band at temperatures up to 1700 K investigated by REMPI spectroscopy,
Chem. Phys. Lett., 1994, 223, 4, 305, https://doi.org/10.1016/0009-2614(94)00469-2
. [all data]
Zhang, Zhang, et al., 2005
Zhang, B.; Zhang, J.; Liu, K.,
Imaging the "missing" bands in the resonance-enhanced multiphoton ionization detection of methyl radical,
J. Chem. Phys., 2005, 122, 10, 104310, https://doi.org/10.1063/1.1859277
. [all data]
Fu, Hu, et al., 2005
Fu, H.B.; Hu, Y.J.; Bernstein, E.R.,
IR/UV double resonant spectroscopy of the methyl radical: Determination of ν[sub 3] in the 3p[sub z] Rydberg state,
J. Chem. Phys., 2005, 123, 23, 234307, https://doi.org/10.1063/1.2135772
. [all data]
Callear and Metcalfe, 1976
Callear, A.B.; Metcalfe, M.P.,
Oscillator strengths of the bands of the B2 A´1---X2 A´´2 system of CD3 and a spectroscopic measurement of the recombination rate comparison with CH3,
Chem. Phys., 1976, 14, 2, 275, https://doi.org/10.1016/0301-0104(76)80045-6
. [all data]
Westre, Gansberg, et al., 1992
Westre, S.G.; Gansberg, T.E.; Kelly, P.B.; Ziegler, L.D.,
Structure and dynamics of higher vibronic levels in the methyl radical Rydberg 3s state,
J. Phys. Chem., 1992, 96, 9, 3610, https://doi.org/10.1021/j100188a012
. [all data]
Settersten, Farrow, et al., 2003
Settersten, T.B.; Farrow, R.L.; Gray, J.A.,
Coherent infrared--ultraviolet double-resonance spectroscopy of CH3,
Chem. Phys. Lett., 2003, 370, 1-2, 204, https://doi.org/10.1016/S0009-2614(03)00062-9
. [all data]
Holt, McCurdy, et al., 1984
Holt, P.L.; McCurdy, K.E.; Weisman, R.B.; Adams, J.S.; Engel, P.S.,
Transient CARS spectroscopy of the ν1 band of methyl radical,
J. Chem. Phys., 1984, 81, 7, 3349, https://doi.org/10.1063/1.448000
. [all data]
Kelly and Westre, 1988
Kelly, P.B.; Westre, S.G.,
Resonance Raman spectroscopy of the methyl radical,
Chem. Phys. Lett., 1988, 151, 3, 253, https://doi.org/10.1016/0009-2614(88)85284-9
. [all data]
Triggs, Zahedi, et al., 1992
Triggs, N.E.; Zahedi, M.; Nibler, J.W.; DeBarber, P.; Valentini, J.J.,
High resolution study of the ν1 vibration of CH3 by coherent Raman photofragment spectroscopy,
J. Chem. Phys., 1992, 96, 3, 1822, https://doi.org/10.1063/1.462083
. [all data]
Zahedi, Harrison, et al., 1994
Zahedi, M.; Harrison, J.A.; Nibler, J.W.,
266 nm CH3I photodissociation: CH3 spectra and population distributions by coherent Raman spectroscopy,
J. Chem. Phys., 1994, 100, 6, 4043, https://doi.org/10.1063/1.466342
. [all data]
Hadrich, Hefter, et al., 1996
Hadrich, S.; Hefter, S.; Pfelzer, B.; Doerk, T.; Jauernik, P.; Uhlenbusch, J.,
Determination of the absolute Raman cross section of methyl,
Chem. Phys. Lett., 1996, 256, 1-2, 83, https://doi.org/10.1016/0009-2614(96)00411-3
. [all data]
Tan, Winer, et al., 1972
Tan, L.Y.; Winer, A.M.; Pimentel, G.C.,
Infrared Spectrum of Gaseous Methyl Radical by Rapid Scan Spectroscopy,
J. Chem. Phys., 1972, 57, 9, 4028, https://doi.org/10.1063/1.1678876
. [all data]
Yamada, Hirota, et al., 1981
Yamada, C.; Hirota, E.; Kawaguchi, K.,
Diode laser study of the ν2 band of the methyl radical,
J. Chem. Phys., 1981, 75, 11, 5256, https://doi.org/10.1063/1.441991
. [all data]
Wormhoudt and McCurdy, 1989
Wormhoudt, J.; McCurdy, K.E.,
A measurement of the strength of the ν2 band of CH3,
Chem. Phys. Lett., 1989, 156, 1, 47, https://doi.org/10.1016/0009-2614(89)87078-2
. [all data]
Stancu, Ropcke, et al., 2005
Stancu, G.D.; Ropcke, J.; Davies, P.B.,
Line strengths and transition dipole moment of the ν[sub 2] fundamental band of the methyl radical,
J. Chem. Phys., 2005, 122, 1, 014306, https://doi.org/10.1063/1.1812755
. [all data]
Snelson, 1970
Snelson, A.,
Infrared matrix isolation spectrum of the methyl radical produced by pyrolysis of methyl iodide and dimethyl mercury,
J. Phys. Chem., 1970, 74, 3, 537, https://doi.org/10.1021/j100698a011
. [all data]
Jacox, 1977
Jacox, M.E.,
Matrix isolation study of the infrared spectrum and structure of the CH3 free radical,
J. Mol. Spectrosc., 1977, 66, 2, 272, https://doi.org/10.1016/0022-2852(77)90217-X
. [all data]
Lee and Lee, 2011
Lee, Y.-F.; Lee, Y.-P.,
Infrared absorption of CH3SO2 observed upon irradiation of a p-H2 matrix containing CH3I and SO2,
J. Chem. Phys., 2011, 1334, 12, 124314, https://doi.org/10.1063/1.3567117
. [all data]
Amano, Bernath, et al., 1982
Amano, T.; Bernath, P.F.; Yamada, C.; Endo, Y.; Hirota, E.,
Difference frequency laser spectroscopy of the ν3 band of the CH3 radical,
J. Chem. Phys., 1982, 77, 11, 5284, https://doi.org/10.1063/1.443797
. [all data]
Tanarro, Sanz, et al., 1994
Tanarro, I.; Sanz, M.M.; Bermejo, D.; Domingo, C.; Santos, J.,
Double modulation-high resolution infrared spectroscopic technique: The ν3 band of the CH3 radical and excited states of CH4 in a hollow cathode discharge,
J. Chem. Phys., 1994, 100, 1, 238, https://doi.org/10.1063/1.466991
. [all data]
Tanarro, Sanz, et al., 1994, 2
Tanarro, I.; Sanz, M.M.; Domingo, C.; Bermejo, D.; Santos, J.; Domenech, J.L.,
Transition dipole moment of the .nu.3 band of CH3,
J. Phys. Chem., 1994, 98, 23, 5862, https://doi.org/10.1021/j100074a009
. [all data]
Bethardy and Macdonald, 1995
Bethardy, G.A.; Macdonald, R.G.,
Direct measurement of the transition dipole moment of the v3 asymmetric C--H stretching vibration of the CH3 radical,
J. Chem. Phys., 1995, 103, 8, 2863, https://doi.org/10.1063/1.470499
. [all data]
Davis, Anderson, et al., 1997
Davis, S.; Anderson, D.T.; Duxbury, G.; Nesbitt, D.J.,
Jet-cooled molecular radicals in slit supersonic discharges: Sub-Doppler infrared studies of methyl radical,
J. Chem. Phys., 1997, 107, 15, 5661, https://doi.org/10.1063/1.474259
. [all data]
Scherer, Aniolek, et al., 1997
Scherer, J.J.; Aniolek, K.W.; Cernansky, N.P.; Rakestraw, D.J.,
Determination of methyl radical concentrations in a methane/air flame by infrared cavity ringdown laser absorption spectroscopy,
J. Chem. Phys., 1997, 107, 16, 6196, https://doi.org/10.1063/1.474284
. [all data]
Kawaguchi, 2001
Kawaguchi, K.,
High-resolution Fourier transform infrared spectra of the CH,
Can. J. Phys., 2001, 79, 2-3, 449, https://doi.org/10.1139/p00-093
. [all data]
Pacansky and Bargon, 1975
Pacansky, J.; Bargon, J.,
Low temperature photochemical studies on acetyl benzoyl peroxide. Observation of methyl and phenyl radicals by matrix isolation infrared spectroscopy,
J. Am. Chem. Soc., 1975, 97, 23, 6896, https://doi.org/10.1021/ja00856a066
. [all data]
Momose, Miki, et al., 1995
Momose, T.; Miki, M.; Uchida, M.; Shimizu, T.; Yoshizawa, I.; Shida, T.,
Infrared spectroscopic studies on photolysis of methyl iodide and its clusters in solid parahydrogen,
J. Chem. Phys., 1995, 103, 4, 1400, https://doi.org/10.1063/1.469763
. [all data]
Tam, Macler, et al., 1997
Tam, S.; Macler, M.; Fajardo, M.E.,
Matrix isolation spectroscopy of laser ablated carbon species in Ne, D[sub 2], and H[sub 2] matrices,
J. Chem. Phys., 1997, 106, 22, 8955, https://doi.org/10.1063/1.474028
. [all data]
Hoshina, Fushitani, et al., 2011
Hoshina, H.; Fushitani, M.; Momose, T.,
Infrared spectroscopy of rovibrational transitions of methyl radicals (CH3, CD3) in solid parahydrogen,
J. Mol. Spectrosc., 2011, 268, 1-2, 164, https://doi.org/10.1016/j.jms.2011.04.014
. [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]
Frye, Sears, et al., 1988
Frye, J.M.; Sears, T.J.; Leitner, D.,
Diode laser spectroscopy of the ν2 band of CD3,
J. Chem. Phys., 1988, 88, 9, 5300, https://doi.org/10.1063/1.454588
. [all data]
Parker, Wang, et al., 1989
Parker, D.H.; Wang, Z.W.; Janssen, M.H.M.; Chandler, D.W.,
Laser ionization spectroscopy of CD3 via the 3pz 2A'2 Rydberg state,
J. Chem. Phys., 1989, 90, 1, 60, https://doi.org/10.1063/1.456466
. [all data]
Sears, Frye, et al., 1989
Sears, T.J.; Frye, J.M.; Spirko, V.; Kraemer, W.P.,
Extended measurements of the ν2 band of CD3 and the determination of the vibrational potential function for methyl,
J. Chem. Phys., 1989, 90, 4, 2125, https://doi.org/10.1063/1.456006
. [all data]
Westre and Kelly, 1989
Westre, S.G.; Kelly, P.B.,
Examination of CD3 vibrational structure by resonance Raman spectroscopy,
J. Chem. Phys., 1989, 90, 12, 6977, https://doi.org/10.1063/1.456273
. [all data]
Miller, Burton, et al., 1989
Miller, J.T.; Burton, K.A.; Weisman, R.B.; Wu, W.-X.; Engel, P.S.,
Cars spectroscopy of gas phase CD3,
Chem. Phys. Lett., 1989, 158, 3-4, 179, https://doi.org/10.1016/0009-2614(89)87317-8
. [all data]
Fawzy, Sears, et al., 1990
Fawzy, W.M.; Sears, T.J.; Davies, P.B.,
Infrared diode laser spectroscopy of the ν3 fundamental of the CD3 radical,
J. Chem. Phys., 1990, 92, 12, 7021, https://doi.org/10.1063/1.458242
. [all data]
Rudolph, Hall, et al., 1996
Rudolph, R.N.; Hall, G.E.; Sears, T.J.,
Measurement of the ν3 fundamental transition moment and vibrational relaxation rates of the CD3 radical,
J. Chem. Phys., 1996, 105, 18, 7889, https://doi.org/10.1063/1.472704
. [all data]
Notes
Go To: Top, Vibrational and/or electronic energy levels, References
- Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
- The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
- Customer support for NIST Standard Reference Data products.