Rate of ionisation of H and Na Rydberg atoms by black-body radiation

Lehman, G. W.

doi:10.1088/0022-3700/16/12/011

Cited by 23 publications

(41 citation statements)

References 10 publications

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“…In the case of n = 30, m = 0 Stark states, the hard-sphere radius r hs is about 10 µm and Γ coll is 2.7 ⋅ 10 −5 cm −1 , which is of the same order of magnitude as ∆E (2) ij,Stark in the relevant range of electric-field strengths. In general, however, interacting atoms separated by a distance r experience slightly different electric-field strengths because of the inhomogeneity of the trapping field so that there is a first-order contribution ∆E (1) ij,Stark (F ) = 1.5 ∂F ∂r a 0 enr (24) to the energy change. Taking into account the typical field gradient (∂F ∂r) of 1.2 ⋅ 10 6 V/m 2 in the trap, one obtains ∆E (1) ij,Stark (F ) (hc) = 2.3 ⋅ 10 −4 cm −1 at a distance of 10 µm corresponding to the hard-sphere radius of an n = 30 Stark state, which is much larger than the estimated collisional broadening and effectively breaks the resonance condition and reduces the values of the hard-sphere radii.…”

Section: A Collision-induced Transitions Between Near-degenerate Levmentioning

confidence: 99%

Radiative and collisional processes in translationally cold samples of hydrogen Rydberg atoms studied in an electrostatic trap

Seiler¹,

Agner²,

Pillet³

et al. 2016

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

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Supersonic beams of hydrogen atoms, prepared selectively in Rydberg-Stark states of principal quantum number n in the range between 25 and 35, have been deflected by 90 ○ , decelerated and loaded into off-axis electric traps at initial densities of ≈ 10 6 atoms/cm −3 and translational temperatures of 150 mK. The ability to confine the atoms spatially was exploited to study their decay by radiative and collisional processes. The evolution of the population of trapped atoms was measured for several milliseconds in dependence of the principal quantum number of the initially prepared states, the initial Rydberg-atom density in the trap, and the temperature of the environment of the trap, which could be varied between 7.5 K and 300 K using a cryorefrigerator. At room temperature, the population of trapped Rydberg atoms was found to decay faster than expected on the basis of their natural lifetimes, primarily because of absorption and emission stimulated by the thermal radiation field. At the lowest temperatures investigated experimentally, the decay was found to be multiexponential, with an initial rate scaling as n −4 and corresponding closely to the natural lifetimes of the initially prepared Rydberg-Stark states. The decay rate was found to continually decrease over time and to reach an almost n-independent rate of more than (1 ms) −1 after 3 ms. To analyze the experimentally observed decay of the populations of trapped atoms, numerical simulations were performed which included all radiative processes, i.e., spontaneous emission as well as absorption and emission stimulated by the thermal radiation. These simulations, however, systematically underestimated the population of trapped atoms observed after several milliseconds by almost two orders of magnitude, although they reliably predicted the decay rates of the remaining atoms in the trap. The calculations revealed that the atoms that remain in the trap for the longest times have larger absolute values of the magnetic quantum number m than the optically prepared RydbergStark states, and this observation led to the conclusion that a much more efficient mechanism than a purely radiative one must exist to induce transitions to Rydberg-Stark states of higher m values. While searching for such a mechanism, we discovered that resonant dipole-dipole collisions between Rydberg atoms in the trap represent an extremely efficient way of inducing transitions to states of higher m values. The efficiency of the mechanism is a consequence of the almost perfectly linear nature of the Stark effect at the moderate field strengths used to trap the atoms, which permits cascades of transitions between entire networks of near-degenerate Rydberg-atom-pair states. To include such cascades of resonant dipole-dipole transitions in the numerical simulations, we have generalized the two-state Förster-type collision model used to describe resonant collisions in ultracold Rydberg gases to a multi-state situation. It is only when considering the combined effects of collisional and radiative pr...

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Section: A Collision-induced Transitions Between Near-degenerate Levmentioning

confidence: 99%

Radiative and collisional processes in translationally cold samples of hydrogen Rydberg atoms studied in an electrostatic trap

Seiler¹,

Agner²,

Pillet³

et al. 2016

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

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show abstract

“…In Table 1 we list the data of the ionization rate computing for the Rydberg sodium atom in the states (17,18D,18P) at temperatures of 300 K and 500 K: Th5 -our (relativistic MP theory) data [3], Th1-theory (nonrelativistic Simons-Fues MP) by Glukhov-Ovsyannikova [9], Th2-theory of Lehman [8], Th3-quasiclassical model by Dyachkov-Pankratov [10], Th4-theory by Beterov et al [1] and E1 -experimental data [4,5]. In whole there is physically reasonable agreement between the theoretical and experimental data.…”

Section: Resultsmentioning

confidence: 99%

“…In fact this is a beginning of a new epoch in the atomic physics with external electromagnetic field. It has stimulated a great number of papers on the ad and dc Stark effect [1][2][3][4][5][6][7][8][9][10][11][12]. The experiments with Rydberg atoms had very soon resulted in the discovery of an important ionization mechanism, provided by unique features of the Rydberg atoms.…”

Section: Introductionmentioning

confidence: 99%

Relativistic theory of excitation and ionization of Rydberg atomic systems in a Black-body radiation field

Buyadzhi

Заічко

Gurskaya

et al. 2017

J. Phys.: Conf. Ser.

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“…In Table 1 we present results of the ionization rate calculation for the Rydberg sodium atom in the states (17,18D, 18P) at temperatures of 300 K and 500 K: Th5 -our (relativistic MP theory) data, E1 -experimental data by Kleppner etal and Burkhardt etal [4] MP) by Glukhov-Ovsyannikova [9], Th2-theory of Lehman [8], Th3-quasiclassical model by Dyachkov-Pankratov [10] and Th4-theory by Beterov et al [1]. Overall, there is physically reasonable agreement between the theoretical and experimental data.…”

Section: Resultsmentioning

confidence: 99%

“…In fact this is a beginning of a new epoch in the atomic physics with external electromagnetic field. It has stimulated a great number of papers on the ac and dc Stark effect [1][2][3][4][5][6][7][8][9][10][11][12]. Conversely, the experiments with Rydberg atoms had very soon resulted in the discovery of an important ionization mechanism, provided by unique features of the Rydberg atoms.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopy of Rydberg atoms in a Black-body radiation field: Relativistic theory of excitation and ionization

Свинаренко

Khetselius

Buyadzhi

et al. 2014

J. Phys.: Conf. Ser.

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IntroductionA great progress in experimental laser physics and appearance of the so called tunable lasers allows one to access the highly excited Rydberg states of atoms. In fact this is a beginning of a new epoch in the atomic physics with external electromagnetic field. It has stimulated a great number of papers on the ac and dc Stark effect [1][2][3][4][5][6][7][8][9][10][11][12]. Conversely, the experiments with Rydberg atoms had very soon resulted in the discovery of an important ionization mechanism, provided by unique features of the Rydberg atoms. Relatively new topic of the modern theory is connected with consistent treating the Rydberg atoms in a field of the Blackbody radiation (BBR). It should be noted that the BBR is one of the essential factors affecting the Rydberg states in atoms [1]. The account for the ac Stark shift, fast redistribution of the levels' population and photoionization provided by the environmental BBR became of a great importance for successfully handling atoms in their Rydberg states.The most popular theoretical approaches to computing ionization parameters of the Rydberg atom in the BBR are based on the different versions of the model potential (MP) method, quasiclassical models. We mention a simple approximation for the rate of thermal ionization of Rydberg atoms, based on the results of our systematic calculations in the Simons-Fues MP [1]. In fact, using the MP approach is very close to the quantum defect method and other semi-empirical methods, which were also widely used in the past few years for calculating atom-field interaction amplitudes in the lowest orders of the perturbation theory. The significant advantage of the Simons-Fues MP method in comparison with other models is the possibility of presenting analytically (in terms of the hypergeometric functions) the characteristics for arbitrarily high orders, related to both bound-bound and bound-free transitions. Naturally, the standard methods of the theoretical atomic physics, including the Hartree-Fock and Dirac-Fock approximations, should be used in order to determine the thermal ionization characteristics of neutral and Rydberg atoms [2]. Note that the correct treatment of the heavy Rydberg atoms parameters in an external electromagnetic field requires using strictly relativistic models. Here we apply an energy approach [11][12][13][14][15] and relativistic perturbation theory (PT)

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Rate of ionisation of H and Na Rydberg atoms by black-body radiation

Cited by 23 publications

References 10 publications

Radiative and collisional processes in translationally cold samples of hydrogen Rydberg atoms studied in an electrostatic trap

Radiative and collisional processes in translationally cold samples of hydrogen Rydberg atoms studied in an electrostatic trap

Relativistic theory of excitation and ionization of Rydberg atomic systems in a Black-body radiation field

Spectroscopy of Rydberg atoms in a Black-body radiation field: Relativistic theory of excitation and ionization

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