Thermodynamic study of the CsOH(s,l) vaporization by high temperature mass spectrometry

Roki, Fatima-Zhara; Chatillon, C.; Ohnet, Marie-Noëlle; Jacquemain, D.

doi:10.1016/j.jct.2007.09.013

Cited by 15 publications

(11 citation statements)

References 25 publications

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“…Examples of such devices have already been presented by Heyrman et al . for a multiple cell device and Roki et al . for conventional single cells.Provide a set of field apertures with different diameters on a water‐cooled jacket so that the experimenter can remove and clean the aperture after the experiment.…”

Section: Mass Spectrometer and Knudsen Cell Configuration Prerequisitesmentioning

confidence: 98%

“…New Knudsen cell devices – including the heating resistance furnace – have already been described by Chatillon et al ., Heyrman et al ., and Roki et al . Consequently, only the technological choices related to the restricted collimation device will be presented here, i.e., the method for locating the effusion cells as close as possible to the field aperture, as shown in Fig.…”

Section: Effect Of Different Distances Between Aperturesmentioning

confidence: 99%

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Knudsen cell mass spectrometry using restricted molecular beam collimation. I. Optimization of the beam from the vaporizing surface

Nuta

Chatillon

2014

Rapid Comm Mass Spectrometry

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This difference is attributed to the previously approximate assumption that optimizing the restricted collimation solid angle automatically optimizes the sampling of the effused beam included in the restricted collimation angle. Moreover, the location of the evaporating surface for molecules traveling through the collimation device towards the ionization chamber remains an important factor: the distance between the sample evaporation surface and the field aperture is of paramount importance as it changes the molecular transmission to the mass spectrometer or to any target collection device in the conventional Knudsen method.

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Section: Mass Spectrometer and Knudsen Cell Configuration Prerequisitesmentioning

confidence: 98%

Section: Effect Of Different Distances Between Aperturesmentioning

confidence: 99%

Knudsen cell mass spectrometry using restricted molecular beam collimation. I. Optimization of the beam from the vaporizing surface

Nuta

Chatillon

2014

Rapid Comm Mass Spectrometry

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“…If Hg atoms are provided from surface diffusion and then desorbed, their intensities would rapidly decrease when the atoms are far away from the effusion orifice edge. 12,13 Measurements performed at the maximum of the peak (Fig. 5(b)) are not disturbed owing to the restricted collimation device but the re-vaporization phenomenon disturbs the mass loss of the cell as described by the Hertz-Knudsen relationship.…”

Section: Advantages Of the Restricted Collimation Methods And Shutter Usementioning

confidence: 99%

A special reactor coupled with a high‐temperature mass spectrometer for the investigation of the vaporization and cracking of organometallic compounds

Violet

Nuta

Artaud

et al. 2009

Rapid Comm Mass Spectrometry

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A special reactor coupled to a high-temperature mass spectrometer was specifically designed for the study of vaporization and thermal cracking of organometallic precursors. This reactor has two kinds of settings. One is a single Knudsen effusion cell which enables the analysis of the composition of saturated vapors and the determination of the partial pressure of each gaseous molecule in equilibrium with its condensed phase. This cell is an evaporation/sublimation cell (operating from 243 to 473 K), which can be tightly closed--like a vacuum chamber--in order to protect organometallic compounds against moisture and atmospheric components. This cell can be independently weighed usefully to evaluate the equilibrium vapor pressures of the sample using the mass-loss method. During experiments, the effusion aperture is externally opened for direct mass spectrometric measurements. The other setting dedicated to the study of thermal decomposition of gaseous molecules consists of a set of tandem cells: the previously described Knudsen cell and a cracking cell (operating from 293 to 973 K).

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“…The study of CsOH vaporization by Roki et al (12) gives a clear demonstration of the interest of restricted collimation. During the single cell effusion experiments between 570 and 770 K a flow out of the sample is observed around the effusion orifice.…”

Section: = H 2 -Hmentioning

confidence: 99%

“…Acetone and ethanol frequently used in preparing vacuum parts have their main peak at masses 43 and 45 respectively. This is the reason why residual gas analyzers have a resolution in the range 50-80, sufficient to distinguish 12 Considerably higher resolution is required for doublet resolution, for example within the framework of studies involving light elements like Si, C, O, gaseous species like Si + , SiO + , CO + will have to be separated from each other and also from background species such as N 2 + . A resolution of 1550 is required to separate 12 C 16 O + from 28 Si + and of 2500 to separate 12 C 16 O + from 14 N 2 + .…”

Section: Interest Of a High Resolution Instrumentmentioning

confidence: 99%

Transformation of a Double Focusing B-E Mass Spectrometer for Multiple-Cell Knudsen Effusion – Part I: Scientific Concepts

et al. 2013

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Knudsen Effusion Mass Spectrometry (KEMS) is a powerful method in the field of experimental thermodynamics at high temperatures. Since 2005, the long term project of transforming and upgrading a double-focusing VG Micromass 54-38K mass spectrometer for multiple-cell effusion has started at the IM2NP in Marseille/France. The scientific concepts underlying the transformation are presented in this first paper. The molecular beam effusing from the Knudsen cells must be sampled under restricted collimation conditions. The resulting geometric constraints are taken into account in the design of the large main vacuum chamber necessary to house a multiple-cell effusion furnace. Decrease of the molecular transmission between the cell and the ionization source needs to be counterbalanced by an increase in the sensitivity of the ionization source. Other modifications of the instrument are reviewed. The first tests and results will be the subject of a second paper to be published. Overview of the projectThe mass spectrometer, given to us by J. Drowart after he retired from the Université Libre de Bruxelles, is a double focusing 54-38K model manufactured by VG micromass. The analyzer has a B-E geometry in which a magnetic sector, with a radius of 27 cm and 95°, precedes an electrostatic sector of 38.1 cm (15") radius, 81.5°. The ionizer is an electron impact source. The spectrometer is not equipped with any effusion device.The project is to adapt this spectrometer for activity measurements up to 2500 K by the multiple-cell technique according to the concepts developed by C. Chatillon and his coworkers (1, 2, 3) at the CNRS-SIMAP laboratory in Grenoble, France.Concretely, it implies that the molecular beams effusing from the Knudsen cells must be sampled under restricted collimation conditions. The resulting geometric constraints are taken into account in the design of the large main vacuum chamber necessary to house a four-cell effusion furnace. Moreover, decrease in the molecular transmission between the cell and the ionization source needs to be counterbalanced by an increase in the sensitivity of the ionization source.The ion optics between the entrance and the exit slits of the analyzer is not modified. 10.1149/04601.0127ecst ©The Electrochemical Society ECS Transactions, 46 (1) 127-141 (2013) 127 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.218.248.200 Downloaded on 2015-04-12 to IP

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Thermodynamic study of the CsOH(s,l) vaporization by high temperature mass spectrometry

Cited by 15 publications

References 25 publications

Knudsen cell mass spectrometry using restricted molecular beam collimation. I. Optimization of the beam from the vaporizing surface

Knudsen cell mass spectrometry using restricted molecular beam collimation. I. Optimization of the beam from the vaporizing surface

A special reactor coupled with a high‐temperature mass spectrometer for the investigation of the vaporization and cracking of organometallic compounds

Transformation of a Double Focusing B-E Mass Spectrometer for Multiple-Cell Knudsen Effusion – Part I: Scientific Concepts

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