One-Dimension Chains of Structural Defects on the Surface of Sapphire and their Role in Adsorption of Alkali Atoms

Bonch-Bruevich, A. M.; Vartanyan, T. A.; Maksimov, Yu. N.; Przhibel’skiĭ, S. G.; Khromov, V. V.

doi:10.1142/s0218625x9800061x

Cited by 7 publications

(6 citation statements)

References 3 publications

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“…LIAD is understood as a non-thermal effect as opposed to light desorption produced with high power sources in which a significant heating results from light absorption by the substrate. In poly-dimetilsiloxane (PDMS) [11], paraffin [12] and sapphire [13] a frequency threshold in the infrared, similar to that of the photoelectric effect on metals, has been observed. Also, an increasing efficiency of LIAD with light frequency has been reported in several samples [12,14,15].…”

Section: Introductionmentioning

confidence: 87%

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Light-induced atomic desorption and diffusion of Rb from porous alumina

2010

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We present the first study of light induced atom desorption (LIAD) of an alkali atom (Rb) in porous alumina. We observe the variation due to LIAD of the rubidium density in a vapor cell as a function of illumination time, intensity and wavelength. The simple and regular structure of the alumina pores allows a description of the atomic diffusion in the porous medium in which the diffusion constant only depends on the known pore geometry and the atomic sticking time to the pore wall. A simple one-dimensional theoretical model is presented which reproduces the essential features of the observed signals. Fitting of the model to the experimental data gives access to the diffusion constant and consequently the atom-wall sticking time and its dependence on light intensity and wavelength. The non-monotonic dependence of the LIAD yield on the illumination light frequency is indicative of the existence of Rb clusters in the porous medium

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Section: Introductionmentioning

confidence: 87%

“…More recently, LIAD has been studied in porous amorphous materials such as porous silica [15]. LIAD has also been observed on some uncoated surfaces, such as glass [4,7], stainless steel [4], and sapphire [16].…”

Section: Introductionmentioning

confidence: 99%

Light-induced atomic desorption and diffusion of Rb from porous alumina

2010

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“…In this case no interaction between the ablated species through collisions, shock waves, and plasma formation can take place. This allows us to measure the velocity and angular distribution [21] of the ablated species resulting from the initial ablation process, and thus to distinguish between thermal and nonthermal processes [22][23][24][25]. In our experiment we have investigated the time-of-flight distribution of the ablated indium atoms from solid and liquid indium samples by using UV laser pulses in the ns and fs regimes.…”

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confidence: 99%

Short-pulse UV laser ablation of solid and liquid metals: indium

Götz¹,

Stuke²

1997

Applied Physics A: Materials Science & Processing

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Laser-ablation experiments on solid (T = 300 K) and liquid (T = 600 K) indium are reported. The ablation was performed under high vacuum conditions with UV laser pulses at 248 nm and pulse durations of 15 ns and 0.5 ps. The ablated neutral indium atoms were resonantly ionized with a second laser pulse 28 mm above the sample surface and detected in a time-of-flight mass spectrometer. The ablation threshold fluence for solid indium decreases by a factor of 40 from 100 mJ/cm 2 to 2.5 mJ/cm 2 when a 0.5 ps pulse is used instead of a 15 ns laser pulse. Measurements on liquid indium show a different behavior. With 15 ns laser pulses the threshold fluence is lowered by a factor of ∼ 3 from 100 mJ/cm 2 for solid indium to 30 mJ/cm 2 for liquid indium. In contrast, measurements with 0.5 ps laser pulses do not show any change in the ablation threshold and are independent of the phase of the metal at 2.5 mJ/cm 2. This behavior could be explained by thermal diffusion and heat conduction during the laser pulse and demonstrates in an independent way the energy lost into the material when long laser pulses are applied. Time-of-flight measurements to investigate the underlying ablation mechanism show thermal behavior of the ablated indium atoms for both ps and ns ablation and can be fitted to Maxwell-Boltzmann distributions.

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“…The internal energy is not much different from its classical form for kT >> hν. As the temperature approaches absolute zero, the heat capacity decreases as 3 T (Eq. (27)).…”

Section: Discussionmentioning

confidence: 99%