Radiation Processes

We consider two mechanisms of the photon radiation during collisions of the charged projectile with a target: ordinary bremsstrahlung (BrS) and polarizational bremsstrahlung. In the case of ordinary bremsstrahlung the emission of a photon occurs by a charged projectile accelerated in the static field of a target. This is a well-known quantum mechanical process, the basic description of which can be found in textbooks. In the case of polarizational bremsstrahlung the photon emission occurs due to the virtual excitations (polarization) of the target electrons under the action of the field created by a charged projectile. The importance and the fundamental character of the ordinary bremsstrahlung process has been recognized long ago. The polarizational mechanism of the radiation was recognized relatively recently where the first qualitative and quantitative estimates were made of the role of the target polarization in forming the bremsstrahlung spectrum in an electron–atom collision in the range of photon energies close to the atomic ionization potentials.

Figure: Schematic representation of the ordinary and polarizational bremsstrahlung processes.

A general approach to consider the BrS process (both the ordinary and the polarizational) in collisions with many-electron targets is based on a consistent application of quantum mechanics and quantum many-body theory. The main results obtained by using this approach include: (a) application of the many-body theory for accurate calculations of the dynamic generalized polarizability of the target; (b) development of the methods for approximate treatment of the dynamic response of the target; (c) calculation of the total BrS spectra of in collisions of non-relativistic electrons on many-electron atoms over wide range of emitted photon energies including the regions of giant resonances; (d) theoretical and numerical description of the BrS process in electron–cluster collisions; (e) the full relativistic description of the BrS in a charged particle–atom collision. In full, the results obtained by means of the quantum-mechanical description during the whole period of the polarizational BrS history were summarized in a book "Polarizational Bremsstrahlung", A.V. Korol, A.G. Lyalin, and A.V. Solov'yov, Publishing House of St. Petersburg State Polytechnic University, St Petersburg, pp.1-300, (2004) (in Russian).

Relevant publications

• • A.V. Korol, A.G. Lyalin, and A.V. Solov'yov, Polarizational Bremsstrahlung, Publishing House of St. Petersburg State Polytechnic University, St Petersburg, ISBN 5-7422-0565-1, pp.1-300, (2004) (in Russian).

  • A.G. Lyalin and A.V. Solov'yov, Polarizational bremsstrahlung from atomic clusters (Review), Radiation Physics and Chemistry 75, 1358-1379, (2006).

  • A.V. Korol, A.G. Lyalin, A.V. Solov'yov, N. Avdonina, and R.H. Pratt, On the stripping approximation in the bremsstrahlung process, J.Phys. B: At.Mol.Opt.Phys. 35, 1197-1210, (2002).

  • A.V.Korol, A.G.Lyalin, O.I.Obolensky, A.V.Solov'yov, and I.A.Solovjev, A relativistic description of the polarization mechanism of elastic bremsstrahlung, JETP 94, 704-719, (2002).

  • A. V. Korol, A. G. Lyalin, O. I. Obolensky, I. A. Solovjev and A. V. Solov'yov, Polarizational bremsstrahlung on atoms and ions: Relativistic and non-relativistic cases, AIP Conf. Proc.576, 64-67, (2001).

  • A.V.Korol, A.G.Lyalin, O.I.Obolensky, and A.V.Solovy'ov, Manifestation of the Bethe Ridge in the Polarisational Bremsstrahlung Process (Letter), J.Phys. B: At.Mol.Opt.Phys. 33, L179-L186, (2000).

  • A.V.Korol, A.G.Lyalin, and A.V.Solov'yov, Cross section for bremsstrahlung of electrons colliding with atoms with polarizational mechanism taken into account in a broad spectral range, Optics and spectroscopy 86 (4), 486, (1999).

  • A.V.Korol, A.G.Lyalin, O.I.Obolenski, and A.V.Solov'yov, The role of the polarization mechanism for emission of radiation by atoms over a broad photon frequency range, JETP 87 (2), 251-259, (1998).

  • A.V.Korol, A.G.Lyalin, and A.V.Solov'yov, Total bremsstrahlung spectra of 1-25 keV electrons on Ne and Ar, J.Phys. B: At.Mol.Opt.Phys. 30, L115-L121, (1997).

  • L.G.Gerchikov, A.V.Korol, A.G.Lyalin, and A.V.Solov'yov, Giant resonances in photon emission spectra of atoms, clusters and solid state, AIP Conf. Proc. 389, 447-464, (1997).

  • A.V.Korol, A.G.Lyalin, and A.V.Solov'yov, Theoretical treatment of bremsstrahlung spectra in the vicinity of giant atomic resonances, Phys. Rev. A 53, 2230-2238, (1996).

  • A.V.Korol, A.G.Lyalin, A.S.Shulakov, and A.V.Solov'yov, Bremsstrahlung of an intermediate energy electron on La, JETP 82 (4), 631-638, (1996).

  • A.V.Korol, A.G.Lyalin, A.S.Shulakov, and A.V.Solov'yov, Electron bremsstrahlung spectra on La near the 4d-threshold (Letter), J. Phys. B: At.Mol.Opt.Phys. 29, L611-L617, (1996).

  • A.V.Korol, A.G.Lyalin, A.S.Shulakov, and A.V.Solov'yov, Semi-empirical method for the polarizational bremsstrahlung calculation, J. Elect. Spect. Rel. Phenom. 79, 323-326, (1996).

  • A.V.Korol, A.G.Lyalin, and A.V.Solov'yov, Bremsstrahlung in collisions of electrons with atoms and clusters, in "Selected Topics on Electron Physics" ed. D.M.Campbell and H.Kleinpoppen, Plenum Press: NY, pp. 263-278, (1996).

  • A.V.Korol, A.G.Lyalin, A.S.Shulakov, and A.V.Solov'yov, Theoretical treatment of bremsstrahlung spectra in vicinity of giant atomic resonances: application to Ba (Letter), J. Phys. B: At.Mol.Opt.Phys. 28, L155-L160, (1995).

  • A.V.Korol, A.G.Lyalin, and A.V.Solov'yov, New method for the polarizational bremsstrahlung calculation, J. Phys. B: At.Mol.Opt.Phys. 28, 4947-4962, (1995).