Electron Impact Ionization and Excitation of Uracil Molecules


  • M.I. Sukhoviya Uzhgorod National University
  • M.I. Shafranyosh Uzhgorod National University
  • M.M. Chavarga Uzhgorod National University
  • I.I. Shafranyosh Uzhgorod National University






The cross-sections of the formation of positive and negative ions of uracil, a nitrogenous base of nucleic acids, are obtained experimentally. The values for negative ions were shown to reach their maximum of 5.0 × 10–18 cm2 at an energy of bombarding electrons of 1.1 eV. The magnitudes and the energy
dependence were determined for the cross-section of formation of positive uracil ions in the electron energy interval from the formation threshold to 200 eV. The ionization cross-section peak of (1.0 ± 0.1) × 10–15  cm2 was found at an energy of 95 eV. The luminescence spectrum for isolated uracil molecules
consisting of about 20 spectral bands and lines emitted under the action of slow electrons was obtained in the wavelength range 200–500 nm. The uracil radiation spectrum was shown to be driven by the processes of molecular dissociative excitation, dissociative excitation with ionization, and excitation of electron levels in the initial molecule and the molecular ion. The biophysical consequences of the results obtained are discussed.


M.I. Sukhoviya and I.I. Shafranyosh, in Mechanisms of Radiation-Indiced Damage and Recovery of Nucleic Acids (Pushchino Sci. Center of the RAS, Pushchino-na-Oke, 1980), p. 51 (in Russian).

M.I. Sukhoviya, V.N. Slavik, I.I. Shafranyosh, and L.L. Shimon, Biopolim. Klet. 7, 77 (1991).


M.I. Sukhoviya, M.I. Shafranyosh, and I.I. Shafranyosh, in Spectroscopy of Biological Molecules: New Directions (Kluwer, Dordrecht, 1999), p. 281.


V. Cobut, Y. Frongillo, J.P. Patau, T. Goulet, M.J. Fraser, and J.P. Jay-Gerin, Radiat. Phys. Chem. 51, 229 (1998).

I.I. Shafranyosh, M.I. Sukhoviya, and M.I. Shafranyosh, J. Phys. B 39, 4155 (2006).


I.I. Shafranyosh, M.I. Sukhoviya, M.I. Shafranyosh, and L.L. Shimon, Zh. Tekhn. Fiz. 78, No. 12, 7 (2008).

I.I. Shafranyosh and M.I. Sukhoviya, Opt. Spektrosk. 102, 553 (2007).


L.V. Gurvich, G.V. Karachevtsev, V.N. Kondrat'ev, Yu.A. Lebedev, V.A. Medvedev, V.K. Potapov, and Yu.S. Khodeev, Energies of Chemical Bond Breaking. Ionization Potentials and Electron Affinity (Nauka, Moscow, 1974) (in Russian).

G. Hanel, B. Gstir, S. Denifl {it et al., Phys. Rev. Lett. 90, 188104 (2003).


S. Steenken , J.P. Telo, H.M. Novais, and L.P. Candeias, J. Am. Chem. Soc. 114, 4701 (1992).


R.A. Khmel'nitskii and B.P. Terent'ev, Usp. Khim. 48, 854 (1979).

A.A. Polyakova, Molecular Mass Spectrometric Analysis of Organic Compounds (Khimiya, Moscow, 1973) (in Russian).

S. Feil, K. Gluch, S. Matt-Leuber, P. Scheier, J. Limtrakul, M. Probst, H. Deutsh, K. Becker, A. Stamatovic, and T.D. Mark, J. Phys. B 37, 3013 (2004).


NIST Standard Reference Database. Webpage 14. [http://webbook.nist.gov/chemistry]; AIST Spectral Database for Organic Compounds


M.I. Shafranyosh, Nauk. Visnyk Uzhgorod. Univ. Ser. Fiz. 25, 208 (2009).

H. Deutsch, K. Becker, S. Matt, and T.D. Mark, Plasma Phys. Control. Fusion 40, 1721 (1998).


H. Deutsch, P. Scheier, S. Matt-Leubner, K. Becker, and T.D. Mark, Int. J. Mass Spectr. 243, 215 (2005).


H.A. Bethe, Intermediate Quantum Mechanics (Benjamin, New York, 1964).

N.F. Mott and H.S.W. Massey, The Theory of Atomic Collisions (Oxford Univ. Press, Oxford, 1965).

I.P. Vinogradov, V.V. Zemskikh, and N.Ya. Dodonova, Opt. Spektrosk. 36, 596 (1974).

K.P. Huber and G. Herzberg, Molecular Spectra and Molecular Structure IV: Constants of Diatomic Molecules (Van Nostrand, New York, 1979).


G. Herzberg, Molecular Spectra and Molecular Structure I: Spectra of Diatomic Molecules (Van Nostrand, New York, 1950).

R.W. Pearse and A.G. Gaydon, The Identification of Molecular Spectra (Chapman and Hall, London, 1976).


V.V. Skubenich, M.M. Povch, and I.P. Zapesochnyi, in Abstracts of the 7th All-Union Conference on Physics of Electron and Atomic Collisions (Petrozavodsk, 1978), Pt. 1, p. 102.

H.-W. Johims, M. Schwel, H. Baumgartel, and S. Leach, Chem. Phys. 215, 263 (2005).



How to Cite

Sukhoviya М., Shafranyosh М., Chavarga М., & Shafranyosh І. (2012). Electron Impact Ionization and Excitation of Uracil Molecules. Ukrainian Journal of Physics, 57(7), 752. https://doi.org/10.15407/ujpe57.7.752