Single and double photoionisation of Ca atoms between 35 and 42 nm

Sato, Yoshihiro; Hayaishi, T; Itikawa, Yukikazu; Itoh, Yoh; Murakami, Junichi; Nagata, Tetsuo; Sasaki, Taizo; Sonntag, B.; Yagishita, Akira; Yoshino, Masafumi

doi:10.1088/0022-3700/18/2/010

Cited by 77 publications

(24 citation statements)

References 13 publications

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“…The background pressure in the experimental chamber was kept below 1.0×10 −7 Torr. The photoions were detected by a time of flight (TOF) mass spectrometer 25 mounted perpendicular to both the atomic and photon beams, operating in a pulsed extraction mode. The charge-state resolved photoion yield spectra of K + and K 2+ were measured by gated collection of the photoion TOF data obtained in each step of the photon energy scan.…”

Section: Experiments and Resultsmentioning

confidence: 99%

New Window Resonances in the Potassium 3sPhotoabsorption Spectrum

et al. 2002

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The photoion spectrum of atomic potassium was measured over the 3s → np excitation region with the photoion time-of-flight method and monochromatized synchrotron radiation. An unusual spectrum with paired windows structure was found instead of a simple regular Rydberg series. Such subsidiary windows have not been observed in the 3s → np resonances of Ar, which has a closed outer shell. Based on Dirac-Fock calculations, the dual window structure at 36.7 eV and at 37.4 eV was assigned to the 3s −1 3p 6 4s4p resonance. The line shape can be fitted by Fano's formula and the Fano parameters were obtained.

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Section: Experiments and Resultsmentioning

confidence: 99%

New Window Resonances in the Potassium 3sPhotoabsorption Spectrum

et al. 2002

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“…The quantities a and b are the interacting and non-interacting continuum cross sections [1]. figure 1, we find that the first member of the series, the 1s 2 2s2p 5 ( 1 P)3p 2 ( 1 P o ) state, appears as a window type resonance in the single ionization channel. This indicates that the excitation probability of this state is very small compared to the 2p ionization.…”

Section: Resultsmentioning

confidence: 84%

“…The details of the experimental apparatus and procedure have been described in previous papers [2,3]. Briefly, a time-of-flight mass spectrometer was used to separate ions with different charges.…”

Section: Methodsmentioning

confidence: 99%

Observation of high-lying weak autoionizing resonances of Ne, and Mg atoms by charge-separated photoion-yield method

Katō

Osawa

Obara

et al. 2007

J. Phys.: Conf. Ser.

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Photoabsorption and subsequent decay of Na and Mg atoms T Osawa, Y Tohyama, S Obara et al. 3pnp autoionizing resonance series of Ne atom as well as autoionizing resonances in the 2s region of Na and Mg atoms have been studied with monochromatized synchrotron radiation. Use of charge-separated photoion-yield method allowed us to detect these weak resonances in a clarified way in the yield curves of doubly-charged ions. The observed resonance states have been interpreted with the help of MCDF calculations, and the decay processes of these resonance states are discussed briefly. IntroductionAutoionizing resonances in photoabsorption of atoms have been a subject of extensive experimental and theoretical studies. Resonances in rare-gas atoms, which show typical Beutler-Fano profiles [1], have been precisely studied and have often been used for calibrating the photon energies. It is quite natural that the spectrum of inner-shell resonance-excitations or outer-shell resonant double excitation is superimposed on a strong valence ionization continuum. As the inner shell concerned becomes deeper, the resonance states in the spectrum are superimposed on two or more continua and result in not only singly charged ions but also multiply charged ions with respective probabilities. Excitation of such high-lying resonance states is generally quite weak, and we may face a difficulty in discriminating the excitations from the spectra of photoabsorption, total photoions, or photoelectrons, especially for metallic vapors which need high oven temperatures. In this respect, the chargeseparated photoion-yield method as used in this study is often advantageous because weaker resonances are observed in a clarified way in the double and even multiple ionization channels whose background levels are relatively low. In addition, from this kind of measurement, we may obtain information about the decay processes of observed resonance states, as well as the resonance energies and the associated configuration interaction comparing experiment with theoretical calculations.We have carried out an experiment of charge-separated photoion spectroscopy for Ne, Na, and Mg atoms in the region of 2s ionization and have observed weak high-lying autoionizing resonances. In this report, we present the experimental spectra, describe the results of assignment and profile analysis of the resonance features, and, for the Ne and Na cases, mention briefly the decay processes of the resonance states. The details of the assignment based on furthermore precise calculations will be given and discussed in a forthcoming paper. As far as we know, the resonance series observed in this study for Ne and Mg atoms have not been reported previously.

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“…The monochromatized photons entered into the experimental apparatus, which consisted of an ion time of flight (ITOF) mass spectrometer and an electron bombardment oven [18]. A positive pulsed electric field was applied to push ions into the flight tube and the ions were detected with a microchannel plate (MCP).…”

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confidence: 99%

“…To minimize the production of uncontrollable thermal electrons at high temperature, the radiation shield of the oven was water cooled and the distance between the oven and the filament was made larger compared to our previous version [18]. These improved the stability of the beryllium atomic vapor generation.…”

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confidence: 99%

Photoexcitation ofK-shell andL-shell Hollow Beryllium

et al. 2006

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We have observed K-shell and L-shell hollow beryllium atoms (2s(2)2p3s and 1s3s(2)3p) created by photoexcitation using synchrotron radiation. Resonance shapes were fitted to the Fano profile and the parameters were deduced. A Dirac-Fock calculation was performed to identify the configuration of the peaks and to predict other hollow atomic peaks. The results of the calculation were in good agreement with the experimental data. The comparison of the transition strength has revealed that the three-electron photoexcitation to the 1s3s(2)3p configuration is stronger than the two-electron photoexcitation to the 2s(2)2p3s configuration. This is attributed to the large overlap between the 2s orbital of the ground state (1s(2)2s(2)) with the orbital of the L-shell hollow state (1s3s(2)3p).

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Single and double photoionisation of Ca atoms between 35 and 42 nm

Cited by 77 publications

References 13 publications

New Window Resonances in the Potassium 3sPhotoabsorption Spectrum

New Window Resonances in the Potassium 3sPhotoabsorption Spectrum

Observation of high-lying weak autoionizing resonances of Ne, and Mg atoms by charge-separated photoion-yield method

Photoexcitation ofK-shell andL-shell Hollow Beryllium

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