Ar*(3p5 4s, 3P0,2) on Ar(3p6, 1S0) collisions at thermal energies

Robert, J.; Bocvarski, V.; Daunant, I. Colomb de; Vassilev, G.; Baudon, J.

doi:10.1051/jphys:01984004502022500

Cited by 8 publications

(5 citation statements)

References 14 publications

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“…The error results primarily from uncertainty in the background pressure (∼8 × 10 −9 mbar). This total cross section is a combination of elastic metastability exchange [27,28] and direct processes and corresponds well to a value of 5.6 × 10 −14 cm 2 determined at higher energy and with theoretical values [29,30].…”

supporting

confidence: 86%

Trapping Cold Ground State Argon Atoms

Edmunds

Barker

2014

Phys. Rev. Lett.

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We trap cold, ground state argon atoms in a deep optical dipole trap produced by a buildup cavity. The atoms, which are a general source for the sympathetic cooling of molecules, are loaded in the trap by quenching them from a cloud of laser-cooled metastable argon atoms. Although the ground state atoms cannot be directly probed, we detect them by observing the collisional loss of cotrapped metastable argon atoms and determine an elastic cross section. Using a type of parametric loss spectroscopy we also determine the polarizability of the metastable 4s[3/2](2) state to be (7.3±1.1)×10(-39) C m(2)/V. Finally, Penning and associative losses of metastable atoms in the absence of light assisted collisions, are determined to be (3.3±0.8)×10(-10) cm(3) s(-1).

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supporting

confidence: 86%

Trapping Cold Ground State Argon Atoms

Edmunds

Barker

2014

Phys. Rev. Lett.

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“…Nevertheless, due to the gerade-ungerade symmetry of the molecular states of, for instance, the Ar 2 * system, the resonant metastability-exchange process between metastable and ground-state atoms, such as Ar * ( 3 P 0,2 ) + Ar → Ar + Ar * ( 3 P 0,2 ), is an efficient way to produce a metastable atom beam, the quality of which is almost as good as that of the genuine 'natural' nozzle beam. This characteristic of the exchange process has been demonstrated by crossing at 90 • an effusive beam of metastable Ar * atoms with a Campargue nozzle beam of ground-state Ar atom [12]. This has been also observed and analysed in [13], in a collinear configuration of the groundstate and metastable atom beams and in the low energy range (down to 16.5 meV), by means of a time-of-flight analysis.…”

Section: Introductionmentioning

confidence: 78%

Atom diffraction with a ‘natural’ metastable atom nozzle beam

Karam¹,

Wipf²,

Grucker³

et al. 2005

J. Phys. B: At. Mol. Opt. Phys.

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The resonant metastability-exchange process is used to obtain a metastable atom beam with intrinsic properties close to those of a ground-state atom nozzle beam (small angular aperture, narrow velocity distribution). The estimated effective source diameter (15 µm) is small enough to provide at a distance of 597 mm a transverse coherence radius of about 873 nm for argon, 1236 nm for neon and 1660 nm for helium. It is demonstrated both by experiment and numerical calculations with He*, Ne* and Ar* metastable atoms, that this beam gives rise to diffraction effects on the transmitted angular pattern of a silicon-nitride nano-slit grating (period 100 nm). Observed patterns are in good agreement with previous measurements with He* and Ne* metastable atoms. For argon, a calculation taking into account the angular aperture of the beam (0.35 mrad) and the effect of the van der Waals interaction—the van der Waals constant C3 = 1.83+0.1−0.15 au being derived from spectroscopic data—leads to a good agreement with experiment.

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“…one half of the difference between gerade and ungerade amplitudes. Evidently, this signal is maximum at an angle of 90° in the laboratory, corresponding to the maximum polar angle  = , in the center of mass referential frame where the exchange amplitude has to be evaluated [22]. On another hand, at 5 meV, the exchange differential cross section is well under the indiscernibility differential cross section (see figure 3).…”

Section: I-2 Wave Function Scattering Amplitudes and Cross Sectionsmentioning

confidence: 91%

Section: Wave Function Scattering Amplitudes and Cross Sectionsmentioning

confidence: 95%

Low energy collisions of spin-polarized metastable argon atoms with ground state argon atoms

Taillandier-Loize¹,

Perales²,

Baudon³

et al. 2018

J. Phys. B: At. Mol. Opt. Phys.

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The collision between a spin polarized metastable argon atom in Ar* (3p 5 4s, 3 P 2 , M = +2) state slightly decelerated by the Zeeman slower-laser technique and a co-propagating thermal ground state argon atom Ar (3p 6 , 1 S 0 ), both merged from the same supersonic beam, but coming through adjacent slots of a rotating disk, is investigated at center-of-mass energies ranging from 1 to 10 meV. The duration of the laser pulse synchronised with the disk allows the tuning of the relative velocity and thus the collision energy. At these sub-thermal energies, the "resonant metastability transfer" signal is too small to be evidenced. The energy explored range requires using indiscernibility amplitudes for identical isotopes to have a correct interpretation of the experimental results. Nevertheless, excitation transfers are expected to increase significantly at much lower energies as suggested by previous theoretical predictions of potentials 2g ( 3 P 2 ) and 2u ( 3 P 2 ). Limits at ultra-low collisional energies of the order of 1 mK (0.086 µeV) or less, where gigantic elastic cross-sections are expected, will be also discussed. The experimental method is versatile and could be applied using different isotopes of Argon like 36 Ar combined with 40 Ar, as well as other rare gases among which Krypton should be of great interest thanks to the available numerous isotopes present in a natural gas mixture.

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Ar*(3p5 4s, 3P0,2) on Ar(3p6, 1S0) collisions at thermal energies

Cited by 8 publications

References 14 publications

Trapping Cold Ground State Argon Atoms

Trapping Cold Ground State Argon Atoms

Atom diffraction with a ‘natural’ metastable atom nozzle beam

Low energy collisions of spin-polarized metastable argon atoms with ground state argon atoms

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