Observation of Selected Molecular-Orbital X Rays in Coincidence with Separated-Atom<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>K</mml:mi></mml:math>X Rays

O’Brien, Joseph; Liarokapis, E.; Greenberg, Jay

doi:10.1103/physrevlett.44.386

Cited by 18 publications

(6 citation statements)

References 13 publications

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“…To make the double K vacancy contribution negligible, one must have (PK)40.2. K-coincident MO xrays have been measured in 100-to 200-MeV Nb +Nb collisions [1]. Except at small x-ray energies, it was found that the coincident and singles MO xray spectra have approximately the same shape, in agreement with the results shown in Fig.…”

Section: P~ = [C~z Au~-c~u Az~l 2 + P~mo~ Pksupporting

confidence: 73%

“…However, this simple picture is complicated by the very strong Coriolis coupling between the 2 p a and 2pn MO's which occurs for collision systems with combined charge (100 [3,4]. Instead of a pure 2pa, one has two linear combinations of 2pa and 2pn x MO's that can be written as (1) where az~ and az. are given by the Coriolis-coupling equations [5], subject to the initial conditions an, (-oe) = az,(t ) = 1 and as~ (-co)=an, (-oe)=0.…”

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confidence: 97%

“…The K-coincident MO x-rays are emitted with a much larger anisotropy than the non-coincident MO x-rays.Recently, measurements of lsa molecular orbital (MO) x-rays in coincidence with K x-rays emitted after the collision by the projectile and target atoms have been made [1,2]. Since the 2pa MO correlates to the separated-atom (SA)K levels in a symmetric collision, these coincidence experiments allow, in principle, for a selective observation of MO x-rays.…”

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confidence: 99%

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Calculations of molecular-orbital ? separated-atom x-ray coincidences

Anholt

1983

Z Physik A

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The calculated cross section for the production of i s a molecular orbital (MO) x-rays in coincidence with projectile and target K x-rays is a factor of 0.2 to 0.3 smaller than the non-coincident cross section. The K-coincident MO x-rays are emitted with a much larger anisotropy than the non-coincident MO x-rays.Recently, measurements of lsa molecular orbital (MO) x-rays in coincidence with K x-rays emitted after the collision by the projectile and target atoms have been made [1,2]. Since the 2pa MO correlates to the separated-atom (SA)K levels in a symmetric collision, these coincidence experiments allow, in principle, for a selective observation of MO x-rays. Only electronic transitions from the 2pa to the 1 sa MO that leave the vacancy in the 2po-MO are observed. However, this simple picture is complicated by the very strong Coriolis coupling between the 2 p a and 2pn MO's which occurs for collision systems with combined charge (100 [3,4]. Instead of a pure 2pa, one has two linear combinations of 2pa and 2pn x MO's that can be written aswhere az~ and az. are given by the Coriolis-coupling equations [5], subject to the initial conditions an, (-oe) = az,(t ) = 1 and as~ (-co)=an, (-oe)=0.(2) Previous calculations of MO x-ray production [3,4] do not give the selective MO x-ray intensities, because the ultimate fate of the vacancy after the MO x-ray transition is not considered. Ford et al. [6] and Kirsch et al. [7] have suggested a method of calculating coincident MO x-ray cross sections. It is possible to understand their formulations simply if we consider just three levels, the lsa, 2pZ, and 2pn x MO's, occupied by just two electrons of identical spin. We neglect the lly and all other orbitals which cannot couple to the 2pa where r 1 and r 2 are the coordinates for electron 1 and 2. Using first-order perturbation theory, we obtain for the total wavefunction at the end of the collision (t = oe)where C O ~ 1,and C 2 is given by a similar equation. In (5), H' is the radiative perturbation matrix element; thus C 1 is identical to the amplitude Cz for the 2p S electron to radiate a MO x-ray, as given by Anholt [3]. At

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Section: P~ = [C~z Au~-c~u Az~l 2 + P~mo~ Pksupporting

confidence: 73%

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confidence: 97%

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confidence: 99%

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Calculations of molecular-orbital ? separated-atom x-ray coincidences

Anholt

1983

Z Physik A

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“…The MO x-ray 2pl/2 ~r~lSl/2 ~ transition may lead directly to the production of a cascade K x-ray and, therefore, to a "single vacancy" continuum x-ray, K x-ray coincidence event [8]. Kirsch and collaborators [21] have calculated the radiative matrix elements for transitions into the ls~ orbital.…”

Section: B Double Vacancy Contributions To Mo K X-ray Yieldsmentioning

confidence: 99%

“…We report here on the results of a coincidence experiment between continuum and characteristic Krays from Pb+Pb collisions [7]. In contrast to the first of such measurements with the lighter Nb + Nb collision system [8], the extremely high binding energies of the Pb+Pb quasimolecule result in very large spin-orbit coupling and splitting of the molecular orbitals and lead to excitation probabilities for the separated atom K shell electrons which are large and concentrated at small impact parameters. These characteristics of the superheavy quasimolecule result in the dominance of different excitation and radiative matrix elements and lead to MO x-rays in Pb+ Pb encounters which exhibit features qualitatively different from those in lighter, non-relativistic systems.…”

Section: Introductionmentioning

confidence: 97%