Cusp-shape studies with He+ ions at 1.41- and 2.41-a.u. impact velocities

L. Gulys, L. Sarkadi, J. Plinks, A. Kövér, T. Vajnai, Gy Szab, J. Végh, D. Berényi, S. B. Elston

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The electron loss to the continuum (ELC) process was investigated in He+-(He,Ar) collisions at 1.41- and 2.41-a.u. impact velocities. The cusp-shaped energy distributions of electrons ejected into the forward direction were measured in coincidence with the scattered He2+ projectile ions. The shape of these cusps was studied by fitting the multipole series expansion [Meckbach, Nemirovsky, and Garibotti, Phys. Rev. A 24, 1793 (1981)] of the measured spectra using Bnj, the nth-order expansion coefficients of the jth-order Legendre polynomials, as fitting parameters. The observed skewness of the spectra (nonzero 1=B01/B00 values) indicates the importance of the higher-order theories in the description of the distribution of ELC electrons. A dip at the top of the peak (cusp inversion), reflected by a positive 2=B02/B00 value, was observed in the 1.41-a.u. He+-He collision.

Original languageEnglish
Pages (from-to)4535-4541
Number of pages7
JournalPhysical Review A
Issue number7
Publication statusPublished - Jan 1 1992


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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