R.S. Peterson

Production of soft X-ray emitting slow multiply charged ions: Recoil ion spectroscopy

Abstract A study of Ne L-shell vacancy production by S ∼14+ , Cl ∼12+ ions has shown copious production of NeIINeVIII excited states with ∼10 −18 cm 2 cross sections and recoil velocities which may permit significantly higher resolution spectroscopy than is possible with beam-foil methods.

Projectile charge-state dependence in K-shell ionization of neon, silicon, and argon gases by lithium projectiles☆

Abstract The ratios of X-ray yields from the K-shells of gaseous 10 Ne, 14 Si, and 18 Ar by 6 3 Li +1,2,3 and protons were measured at projectile velocities comparable to the orbital velocities of the target K-shells. Projectile charge-state dependence is accounted for quantitatively when electron capture by the projectile and screening of the projectile by its electrons are included.

Polarization measurements of the non-characteristic radiation emitted from collisions between high energy A1 ions

Abstract We have measured the angular distribution of the non-characteristic K X-ray radiation (NCR) in very fast A1-A1 collisions and find that it agrees well with the maximum value predicted by the induced mechanism of Muller et al.

Dipole oscillator strengths for Δ n = 0 transitions in highly ionized sulfur☆

Abstract The foil-excitation method has been used to measure f-values for intra L-shell transitions in highly ionized sulfur.

Radiative transitions in two-electron oxygen

Abstract The foil-excitation method has been used to study the spectra of highly ionized oxygen. Wavelength measurements of transitions between S-, P- and D-states in heliumlike oxygen are reported and compared to theory and other experimental observations.

Autoionizing states in highly ionized oxygen, fluorine and silicon

Excitation processes in atoms or ions usually involve the promotion of one of the least tightly bound outer shell electrons to a higher orbital leading to a state lying below the ionization threshold. It is possible however to form highly excited discrete states that are embedded in the continuum if one or more inner core electrons are raised to outer shells. In the present paper we report on such states in high Z 3-electron ions associated with core excited configurations of the type 1s2snl and 1s2pnl. Such states may autoionize rapidly via the Coulomb interaction unless forbidden to do so by selection rules on this process. These metastable autoionizing states either decay by radiation or autoionize at a slower rate via the weaker magnetic interactions. The lowest lying quartet state in 3-electron ions (1s2s2p)4P 5/2 o is metastable against both autoionization and radiation. Our previously measured lifetimes [1] for this state (in nanoseconds) are: S (1.1), Si (2.1), Ar (0.66), Cl (0.91), F (15), and 0 (25). Radiative decay processes involving core-excited states have also been previously observed. For example, one type of decay is an El transition between two metastable quartet states and another is a similar transition from a core excited state to a singly excited state.

New lines in the XUV spectrum of heliumlike fluorine

Abstract The beam-foil method has been used to study the spectra of highly ionized fluorine in the wavelength region ∼ 70–230A. Two new lines, assigned to the transitions 21,3Po-31,3S in FVIII, are reported.