Quasimolecular K X Rays from Heavy-Ion Collisions

Davis, C.; Greenberg, Jay

doi:10.1103/physrevlett.32.1215

Cited by 43 publications

(9 citation statements)

References 11 publications

(6 reference statements)

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“…In fact, the molecular X-rays have meanwhile been observed by several experimental groups: Saris et al for the system Ar -Ar 10 , Mokier, Stein, and Armbruster for I -Ab 11 , MacDonald et al 12a for 12 C-12 C, Meyerhof et al for Br-Br 12b , Burch et al for Cl-Pb 13 , Kaun et al in the system Ge -Ge 14a , and, most convincingly, Greenberg and Davis for Br -Br and Ni -Ni 15 . The Yale group 15 showed beyond any doubt the very existence of molecular X-rays in heavier ion collisions by investigating and proving the existence of induced radiative transitions, which occur only for radiative molecular transitions (see later).…”

Section: Introductionmentioning

confidence: 90%

“…The lightest system we study, Ni + Ni, is of interest in molecular K-radiation measured by Greenberg et al 15 (Figures 9 -11). The general features of this symmetric system have been discussed in Section X a.…”

Section: Level Diagramsmentioning

confidence: 99%

“…The Yale group 15 showed beyond any doubt the very existence of molecular X-rays in heavier ion collisions by investigating and proving the existence of induced radiative transitions, which occur only for radiative molecular transitions (see later).…”

Section: Introductionmentioning

confidence: 99%

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The Two Centre Dirac Equation

Müller

Greiner

1976

Zeitschrift Für Naturforschung A

101

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During collisions of heavy ions with heavy targets below the Coulomb barrier, adiabatic molecular orbitals are formed for the inner electrons. Deviations from adiabaticity lead to coupling between various states and can be treated by time-dependent perturbation theory. For high charges (Z1+Z2 60) the molecular electrons are highly relativistic. Therefore, the Dirac equation has to be used to obtain the energies and wave functions. The Dirac Hamiltonian is transformed into the intrinsic rotating coordinate system where prolate spheroidal coordinates are introduced. A set of basis functions is proposed which allows the evaluation of all matrix elements of the Dirac Hamiltonian analytically. The resulting matrix is diagonalized numerically. The finite nuclear charge distribution is also taken into account. Results are presented and discussed for various characteristic systems, e. g. Br-Br, Ni-Ni, I-I, Br-Zr, I-Au, U -U, etc.

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Section: Introductionmentioning

confidence: 90%

Section: Level Diagramsmentioning

confidence: 99%

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The Two Centre Dirac Equation

Müller

Greiner

1976

Zeitschrift Für Naturforschung A

101

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“…Continua are observed which stretch from the sharp Kc~ and K/~ x-ray lines emitted by the heavier collision partner to beyond the united atom K/~ x-ray energy. There are no endpoints in the MO x-ray spectra, and no signature in the spectra positively indicating I sa MO x rays [10]. Thus possible contributions from other processes also giving continuum spectra, such as nucleus-nucleus bremsstrahlung (NNB) [12, 13J, secondary electron bremsstrahlung (SEB) [14], and radiative ionization (RI) [15] may also be present.…”

Section: Introductionmentioning

confidence: 97%

A scaling law for molecular orbital X Rays

Anholt¹

1978

Z Physik A

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Absolute molecular-orbital thick-target x-ray yields have been measured for a wide variety of targets using 1.4-MeV/amu 5~ 5SNi, and S6Kr and 2.4-MeV/amu 84Kr beams. A scaling law for calculating two-collision molecular-orbital x-ray yields is derived which fits the shape of the measured yields very well in all collision systems examined, and the intensity within a factor of two for near symmetric ion-atom encounters.

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“…Meyerhof et aL (1973) reported the observation of Is a MO x rays in Br + Br collisions whose end points matched that expected for the UA (Z=70). This work was challenged by Davis and Greenberg (1974), most seriously on the grounds that the end-point energy is not a sufficient clue to the identity of the continuum x rays: first, because high-energy nucleus-nucleus bremsstrahlung (NNB) and x-ray continuum backgrounds (see Sec. IV.B) tend to obscure the end-point position, and second, because continua plotted on a semilogarithmic scale in the absence of such backgrounds show no apparent end point at all .…”

Section: Historical Overviewmentioning

confidence: 99%

X rays from quasimolecules

Anholt

1985

Rev. Mod. Phys.

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In slow heavy-ion-atom collisions, inner-shell electrons with velocities larger than the projectile velocity form diatomic molecular orbitals around the projectile and target nuclei. If a vacancy exists in one of these orbitals, it can decay at some point during collision, emitting an x ray characteristic of the molecular transition energy at that internuclear distance. Since the projectile-target internuclear distance varies during the collision, x-ray continua are seen, which for \so molecular-orbital x rays (transitions to vacancies in the lowest Iscr orbital) stretch toward the united-atom AT-shell binding energy. This paper reviews the theory of and the experimental evidence for molecular-orbital x-ray emission. A historical overview of the development of these studies is given, showing how the theory of quasimolecular x-ray emission has evolved from a semiclassical quasistatic model to a general dynamic theory, including the Coriolis coupling between molecular orbitals making up the initial and final states. X-ray cross section, angular distribution, and other measurements are discussed, and their impact on the development of the theory of molecularorbital x-ray emission is illustrated.

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Quasimolecular K X Rays from Heavy-Ion Collisions

Cited by 43 publications

References 11 publications

The Two Centre Dirac Equation

The Two Centre Dirac Equation

A scaling law for molecular orbital X Rays

X rays from quasimolecules

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