Directional dependence of the surface diffusion of potassium on tungsten (112)

Bayat, B.; Wassmuth, H.-W.

doi:10.1016/0039-6028(83)90478-8

Cited by 40 publications

(14 citation statements)

References 16 publications

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“…However, with periodic boundary conditions, computational limitations do not allow us to chose a period large enough to observe such a profile. Therefore, we first derive an approximate expression of D c (θ) using the phenomenological equations (13)(14)(15)(16)(17)(18)(19), and then solve Eq. (21) with this D c (θ) and periodic boundary conditions.…”

Section: Diffusionmentioning

confidence: 99%

“…For the coverage range 0.5 < θ < 0.66 where the condition T < ε pn /k B is satisfied (see One should keep in mind that the phenomenological equations (13)(14)(15)(16)(17)(18)(19) can be used only for those kinks which are well defined as quasiparticles for a given temperature and a given coverage interval, i.e. the condition T ≪ ε pair /k B must be satisfied.…”

Section: Diffusionmentioning

confidence: 99%

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Mobility and diffusivity in a generalized Frenkel-Kontorova model

et al. 1996

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In this work we used a generalized Frenkel-Kontorova model to study the mobility of water molecules inside carbon nanotubes with small radius at low temperatures. Our simulations show that the mobility of the confined water decreases monotonically increasing the amplitude of the substrate potential at fixed commensurations. On the other hand, the mobility of the water molecules shows a non-monotonic behavior when varying the commensuration. This result indicates that the mobility of the confined fluid presents different behavior regimes depending on the amplitude of the water-nanotube interaction. In order to understand qualitatively these results, we study analytically the driven Frenkel-Kontorova model at finite temperatures. This analysis allows us to obtain the curves of the mobility versus commensurations, at fixed substrate potentials. Such curves shows the existence of three regimes of mobility behavior as a function of the commensuration ratio. Additionally, our study indicates a nontrivial and strong dependence of the mobility with a quantity that can be interpreted as an effective amplitude of the substrate potential, depending on the bare amplitude of the substrate potential, the commensuration ratio and temperature.

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Section: Diffusionmentioning

confidence: 99%

Section: Diffusionmentioning

confidence: 99%

Mobility and diffusivity in a generalized Frenkel-Kontorova model

et al. 1996

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“…4). 20 Na lines were detected first at 2100 • C. The rate of 20 Na is increased by approximately 25 times at 2470 • C due to decreased diffusion delay and increased ionization efficiency. The 20 Na relative efficiency is plotted in Fig.…”

Section: Commissioning Resultsmentioning

confidence: 99%

“…However, data exist for lithium and potassium in tungsten [18,19,20,21]. Rough estimates for diffusion of sodium in tungsten yield 10 −16 m 2 /s < D(T ) < 10 −12 m 2 /s for temperatures in the TI operation region, i.e.…”

Section: Diffusionmentioning

confidence: 99%

Development of a thermal ionizer as ion catcher

Traykov

Dammalapati

et al. 2008

Nuclear Instruments and Methods in Physics Research Section B:

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An effective ion catcher is an important part of a radioactive beam facility that is based on in-flight production. The catcher stops fast radioactive products and emits them as singly charged slow ions. Current ion catchers are based on stopping in He and H 2 gas. However, with increasing intensity of the secondary beam the amount of ion-electron pairs created eventually prevents the electromagnetic extraction of the radioactive ions from the gas cell. In contrast, such limitations are not present in thermal ionizers used with the ISOL production technique. Therefore, at least for alkaline and alkaline earth elements, a thermal ionizer should then be preferred. An important use of the TRIµP facility will be for precision measurements using atom traps. Atom trapping is particularly possible for alkaline and alkaline earth isotopes. The facility can produce up to 10 9 s −1 of various Na isotopes with the inflight method. Therefore, we have built and tested a thermal ionizer. An overview of the operation, design, construction, and commissioning of the thermal ionizer for TRIµP will be presented along with first results for 20 Na and 21 Na.

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“…2 Similar studies on macroscopic anisotropic heterogeneous surface diffusion, however, are very limited. 3 Experimentally, this is presumably because of difficulties inherent in the available experimental techniques.…”

mentioning

confidence: 99%

Anisotropic surface diffusion of CO on Ni(110)

Zhu

Daum

et al. 1991

Phys. Rev. Lett.

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Anisotropic surface diffusion of CO on Ni(l 10) has been studied using the newly developed technique of optical second-harmonic diffraction from a laser-induced CO monolayer grating. Two distinct orthogonal diffusion channels, along [HO] and [001], were found. The measured diffusion coefficients yield the diffusion activation energies Ed(llO) = 1.1 ±0.2 kcal/mol and £^(001) =3.1 ±0.4 kcal/mol and the preexponential factors Z) 0 (lT0) =(3.8 ± 2.0) x 10 " 9 cm 2 /sec and Z) 0 (00l) = (4.8 ±4.4)x 10 " 6 cm 2 /sec. The anisotropy in the surface diffusion appears to cross over at T~~ 160 K.

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Directional dependence of the surface diffusion of potassium on tungsten (112)

Cited by 40 publications

References 16 publications

Mobility and diffusivity in a generalized Frenkel-Kontorova model

Mobility and diffusivity in a generalized Frenkel-Kontorova model

Development of a thermal ionizer as ion catcher

Anisotropic surface diffusion of CO on Ni(110)

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