Photoelectron-photoelectron coincidence spectroscopy

Price, S. D.; Eland, J. H. D.

doi:10.1016/0368-2048(90)85054-d

Cited by 37 publications

(18 citation statements)

References 26 publications

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“…Furthermore, the unfavoured ones are excited with intensities that are not very different from the favoured ones. These observations are in good agreement with the studies of the heavier rare gases by Halt et al [13] and the studies of Price and Eland [11,12] in argon and xenon but in disagreement with the results of Labtanquie et al [10] who observed the formation of the 3pe ground state almost exclusively in their study of argon. The disagreement with the latter work may be due to the limited statistical accuracy of their data and also to the fact that the observations were made more than 10 eV above threshold.…”

Section: Experimental Methodssupporting

confidence: 80%

“…The results of the first ever photoelectron-photoelectron coincidence (PEPECO) experiment, in argon, performed by Lablanquie et al [10] seemed to demonstrate a strong state selection since they observed mostly the 3p state. However the studies by Price and Eland [11,12] in argon and xenon were in disagreement with these earlier results since these authors also observed transitions to other ionic states. Very recently Hall et al [13] reported observations on the partial cross sections for near-threshold photo-double ionisation in all the heavier rare gases using a sensitive PEPECO experiment in which coincidences were measured between threshold (zero energy) photoelectrons and finite fixed energy ( 100 meV) photoelectrons.…”

Section: Introductionmentioning

confidence: 50%

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Threshold photoelectrons coincidence spectroscopy of the rare gases Ne, Ar, Kr and Xe

Hall

Dawber

McConkey

et al. 1992

Z Phys D - Atoms, Molecules and Clusters

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Abstract. Threshold single photon double ionisation of the rare gases neon, argon, krypton and xenon has been studied in an electron-electron coincidence experiment. A new technique has been used where only near-zero energy electrons are detected and these are measured in coincidence. The spectrometer used here employs the penetrating field technique which provides very high detection efficiency, sensitivity and energy resolution. Relative partial double ionisation cross sections have been measured at threshold for the n p4(3p, 1D and 1S) states of Ne + +, Ar + +, Kr + + and Xe + + and the n snpS(3p and 1p) states of Ne + --, Ar + + and Kr + +. The observed relative cross sections are in general agreement with a propensity rule for excitation of these states, except for the case of neon.

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Section: Experimental Methodssupporting

confidence: 80%

Section: Introductionmentioning

confidence: 50%

Threshold photoelectrons coincidence spectroscopy of the rare gases Ne, Ar, Kr and Xe

Hall

Dawber

McConkey

et al. 1992

Z Phys D - Atoms, Molecules and Clusters

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“…3 was stimulated by the controversial discussion of a possible final-state selectivity in the case of the Ar 3s 2 3p 43p_, 1D_ ' and 1S-double photoionization as outlined in the introduction. In the following we discuss the formation of the 3s 3p 5 ap_ and 3P-states within the context of the Wannier model as it was used in [ 13,15,[20][21][22]25]. Therein what is called the Wannier model is a combination of classically determined electron emission characteristics dominated by the Wannier ridge and of symmetry properties of the quantum mechanical wave function of the two escaping electrons.…”

Section: Hi Results and Discussionmentioning

confidence: 99%

“…Their arguments supporting a state selectivity were based on the symmetry properties of the two-electron wavefunctions of the escaping electrons developed in the Wannier theory [14,[16][17][18][19]. In contrast, first in xenon [20] and later also in argon [13,[21][22][23] This paper describes the application of the PIFS to the Ar 3s 3p 5 ip_ and 3p-double photoionization. In comparison with the mentioned earlier investigation [10], in the new experiment described here a significant reduction of the uncertainties of the cross sections for the 3s 3p 5 1p_ and 3p-double photoionization was achieved.…”

Section: Introductionmentioning

confidence: 98%

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Double photoionization of argon into the 3s3p 5 1 P- and3 P-states

Möbus

Schartner

Ehresmann

et al. 1994

Z Phys D - Atoms, Molecules and Clusters

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Abstract. Double photoionization of argon was studied by photon induced fluorescence spectroscopy (PIFS). Cross sections for the double photoionization into the 3s3p5 ~p, 3p states of Ar + + are presented for exciting photon energies between threshold and 120 eV. In the threshold range the energy dependencies of these cross sections were determined for the first time. Singlet and triplet states are populated with comparable probabilities at equal excess energies, in contrast to predictions of the extended Wannier theory. At h v = 100 eV the spin-orbit splitting of the 3s3p 5 3p state was resolved, and a cross section for the production of Ar + + 3s°3p 6 ~S 0 was determined for the first time.

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Electron‐pair ion coincidence (EPIC) techniques for spectrometry and state‐selective chemistry of doubly charged ions

Eland

Mathur

Brenton

1991

Rapid Comm Mass Spectrometry

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Multiple-coincidence techniques involving detection of two near-threshold electrons in coincidence with each other and with product ions are proposed to measure spectra of doubly charged ions and the decay of their energy-selected states. The new techniques are demonstrated by laboratory experiments on double photoionization of C 0 2 and SOz.Significant advances have been made recently in our knowledge of doubly charged molecular ions,'.2 both by experimental and theoretical methods. Spectra of these species can be seen using techniques of double charge t r a n~f e r~.~ and Auger s p e c t r o s~o p y~,~ and their properties can be studied by several mass spectrometric, coincidence and translational spectroscopy Interpretation of the experimental work has benefited from advances in ab initio theory, by which the structures, energies and some reactions of these ions can now be predicted with useful accuracy."There is at present one general technique for stateselective study of doubly charged ions in both bound and dissociative states, namely detection of ions in coincidence with analysed Auger electrons, following the creation of an inner shell vacancy."," The purpose of this paper is to propose and demonstrate a new method to achieve state selection and to obtain spectra of doubly charged ions by photoionization.The basic idea of the technique is to detect in coincidence pairs of photoelectrons both of whose energies lie in a narrow range close to zero. If both energies are constrained to be less than a limit Em,, then the states of the doubly charged ion formed must lie within an energy range from hu to hu -2E,,,, where hu is the photon energy. The yield of the coincident electrons as a function of wavelength will give the spectrum, while the fates of the doubly charged ions selected at a given wavelength can be determined from the mass spectra of ions, whether singly or in pairs, in coincidence with the electrons. The special virtue of near-zero energy electrons is that they can be detected with high efficiency using very simple apparatus. In a 'steradiancy analyser' ,I' low-energy electrons formed in an electric field are selected by the fact that their trajectories are parallel to the field lines, while the great majority of higher-energy electrons have non-parallel velocity components.Three main experiments can be done by this method: 1. Spectra of single ions in coincidence with electron pairs, of which an example is given below, provide complete mass spectra from double ionization. They show parent and fragment doubly charged ions and the singly charged ions from charge separation, all in the same spectra, directly revealing the true relative importance of the different pathways. Current techniques look at doubly charged products and chargeseparation products in separate experiments, which are difficult to normalize to one another. 2. Two-parameter charge-separation spectra of pairs of ions in coincidence with electron pairs, also demonstrated below, identify the dissociation pathways and will reveal the d...

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Photoelectron-photoelectron coincidence spectroscopy

Cited by 37 publications

References 26 publications

Threshold photoelectrons coincidence spectroscopy of the rare gases Ne, Ar, Kr and Xe

Threshold photoelectrons coincidence spectroscopy of the rare gases Ne, Ar, Kr and Xe

Double photoionization of argon into the 3s3p 5 1 P- and3 P-states

Electron‐pair ion coincidence (EPIC) techniques for spectrometry and state‐selective chemistry of doubly charged ions

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