Cyclotron Resonance Studies of Chemi-ionization in the O+C2H2 Reaction


DURING an investigation into the kinetics of the O+C2H2 reaction in a flow system by electron spin resonance (ESR) spectroscopy (unpublished results of J. N. B. and R. S. T.) an intense signal with an effective g value of 2.00 was detected. The following evidence showed that it was the result of cyclotron resonance of free electrons. The signal appeared with a TE012 cavity, with electric lines of force perpendicular to the d.c. magnetic field, but not with a cavity operating in the TE102 mode. The application of a d.c. potential to tungsten electrodes inserted upstream of the cavity reduced the signal and produced a measurable current but did not affect the ESR signals. The signal was up to 107 times more intense than that of the normal radical electric dipole transition and was characteristically broad and unsymmetrical with a g value of 2.00 (refs. 1 and 2). The signal versus reaction time profile was similar in shape to those reported3 for the system using Langmuir probe and mass spectrometer detection.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Schreider, J., and Hofmann, F. W., Phys. Rev., 116, 244 (1959).

  2. 2

    Bayes, K. D., Kivelson, D., and Wong, S. C., J. Chem. Phys., 37, 1217 (1962).

  3. 3

    Fontijn, A., Miller, W. J., and Hogan, J. M., Tenth Intern. Symp. on Combustion, 545 (The Combustion institute, Pittsburgh, 1965).

  4. 4

    Arrington, C. A., Brennen, W., Glass, G. P., Michael, J. V., and Niki, H., J. Chem. Phys., 43, 1489 (1965).

  5. 5

    James, G. S., thesis, Univ. Essex (1967).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

BRADLEY, J., TSE, R. Cyclotron Resonance Studies of Chemi-ionization in the O+C2H2 Reaction. Nature 222, 474 (1969).

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.