Optics and Spectroscopy

Resonant structure of the formation of doubly charged ions in multiphoton ionization of Sr atoms in the infrared spectral region

І. І. Бондар, В. В. Суран

Published Jun 1, 2000• 2 citations

Abstract

The process of forming doubly charged ions in ionization of Sr atoms by laser radiation in the frequency region of 8200–9100 cm −1 is studied experimentally. The resonant structure of the yield of these ions as a function of the radiation frequency is found to be determined by the excitation of strongly perturbed states of Sr atoms.

DOI: 10.1134/1.626886

Related papers

Resonant structure in doubly charged ion formation during multiphoton ionization of Sr and Ba atoms by infrared laser radiation

І. І. Бондар, В. В. Суран, M. I. Dudich

Experimental investigations of resonant structure in doubly charged ion (A 2+ ) formation were carried out during Sr and Ba atom ionization by infrared laser radiation (ω = 8400-9100 cm -1 ). It has been shown that in this case the mechanism of ion formation is a two-electron process - the ions are produced immediately from the neutral atoms. It has been found for the first time that the resonant structure in A 2+ ion formation in such conditions is due to the excitation and ionization of neutral-atom mixed states. The atomic-state mixing in this case results from the Stark effect provided that the polarizability of these states is very high.

Journal of Physics B Atomic Molecular and Optical PhysicsSep 20, 200021 citations

Resonance structure of doubly-charged-ion production during laser dielectronic ionization of atoms

І. І. Бондар, В. В. Суран

The resonance structure of doubly-charged-ion production during the ionization of Ba atoms by infrared radiation (color-center laser radiation) is identified. It is shown that this structure is due to the excitation of states of the neutral Ba atom which are strongly perturbed as a result of the Stark effect under conditions such that the dynamic polarizability has large absolute values and depends strongly on the frequency of the radiation.

Journal of Experimental and Theoretical Physics LettersDec 1, 199812 citations

The two-electron mechanism of the formation of doubly charged ions by the multiphoton ionization of Ba atoms with two-laser radiation

І. І. Бондар, В. В. Суран

The experimental investigation of the formation of doubly charged ions by the multiphoton ionization of Ba atoms by simultaneous irradiation with the fundamental radiation of a colour centres laser (ω = 8800–8880 cm −1 ) and its second harmonics was carried out. A two-electron mechanism was observed to be responsible for the formation of these ions; they are formed as a result of the excitation and subsequent ionization of strongly perturbed states of neutral Ba atoms.

Journal of Physics B Atomic Molecular and Optical PhysicsAug 7, 200212 citations

Probability of the two-electron mechanism of the formation of doubly charged barium ions as a function of laser radiation intensity

І. І. Бондар, В. В. Суран, Denys I. Bondar

The formation of singly and doubly charged ions upon nonlinear ionization of barium atoms is studied as a function of the frequency and intensity of a 8800-8920-cm−1 IR color center laser. Barium atoms are ionized via the four-photon resonance with the strongly perturbed bound 6p 2 1 D 2 state. Doubly charged barium ions are produced by a two-electron mechanism. It is found that the probability of the formation of doubly charged ions under these conditions linearly depends on the laser radiation intensity.

Journal of Experimental and Theoretical PhysicsJun 1, 20131 citation

Peculiarity of formation of doubly charged ions upon multiphoton ionization of barium atoms by linearly and circularly polarized radiation

В. В. Суран, І. І. Бондар

The process of formation of doubly charged ions upon multiphoton ionization of barium atoms by linearly and circularly polarized radiation of dye lasers is studied in the frequency range from 16 600 to 17 900 cm-1. A large number of resonance maxima in the yield of Ba+ and Ba2+ ions were observed upon tuning the radiation frequency. It is unambiguously proved that most resonance maxima in the yield of Ba2+ ions are associated with the resonance transitions in the spectrum of Ba+ ions. This fact confirms the cascade mechanism of formation of Ba2+ ions in the frequency range of localization of these maxima. But the number of the resonant maxima in Ba2+ ions yield do not identified by transitions both in spectra of Ba atom and Ba+ ion. This fact indicates on realization of the noncascade mechanism of Ba2+ ions formation in the frequency range of these maxima.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEJun 15, 20070 citations

Doubly charged ions resulting from the multiphoton atomic ionization of alkaline-earth metals

В. В. Суран, І. І. Бондар

The study of the creation of doubly charged ions upon the laser-induced multiphoton ionization of alkaline-earth metals is reviewed. The results show that the features of the creation of the doubly charged ions depend on the spectral range of the ionizing laser radiation. In the ionization of the alkaline-earth atoms by the visible laser radiation, the cascade creation of the doubly charged ions is predominantly implemented when the ions result from the multiphoton ionization of singly charged ions created in the presence of the same laser pulse. In the multiphoton ionization of the alkaline-earth atoms by the IR laser radiation, the two-electron process occurs when the doubly charged ions are directly created from neutral atoms owing to the ionization via induced resonances with strongly perturbed states of these atoms.

Laser PhysicsAug 1, 20094 citations