Optical Studies of Thin Films of Cryocondensed Mixtures of Water and Admixture of Nitrogen and Argon

Sokolov, D.; Yerezhep, D.; Vorobyova, Olga; Ramos, Miguel A.; Shinbayeva, A.

doi:10.3390/ma15217441

Cited by 5 publications

(5 citation statements)

References 29 publications

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“…This pattern may indicate the growth of structures that are denser than amorphous carbon dioxide condensates or amorphous water ice. This interesting pattern can be observed in other gas hydrate mixtures as well [42]. Moreover, the data in table 1 suggest that the refractive index for the mixture of H2O(85%) + CO2(15%) increases up to 80 K and then decreases at 110 K as the condensation temperature rises.…”

Section: Resultsmentioning

confidence: 52%

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A Semi-Automatic Examination of Co2 Structures in Thin Films at Low Temperatures

Golikov,

Yerezhep,

Yerlanov

2023

ijmph

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The aim of this paper is to study the IR spectra of thin films of a mixture of carbon dioxide and water obtained via vapor deposition in the temperature range of 11-180 K. Based on the analysis of the spectra, we examine the formation of hydrates and clathrates that are of interest to modern condensed matter physics. To carry out this research, the methods of IR spectroscopy, mass spectroscopy, and optical analysis of the thin films formed were utilized. Fourier transform infrared spectroscopy is one of the most reliable methods for the identification of the molecular composition and structural states of molecular mixtures. Additional tools, such as mass spectroscopy and interference patterns, were used to confirm the formation of specific structures in the carbon dioxide and water mixture. During the experiments, CO2 hydrate and gas hydrate structures formed in the mixture. The gas hydrates that formed in the mixture can be classified as sI-type hydrates. The hydrate compounds hold CO2 molecules in their structures, preventing them from sublimating at 93 K (the sublimation temperature of unbound CO2 at a pressure of P = 0.5µTorr). At the same time, the sublimation temperature of CO2 molecules bound in hydrate structures becomes equal to 147-150 K. For the selected concentration of CO2 (25%) -H2O (75%), the changes in the observed spectra and the data obtained using mass spectroscopy indicate incomplete hydration of the mixture. Some of the CO2 molecules remain unbound and sublimate earlier. The increase in the refractive index as the concentration of H2O in the mixture approaches 25% indicates the growth of structures that are denser compared to amorphous CO2 condensates and amorphous H2O ice. The results expand the current knowledge of the clathrate and hydrate formation processes in mixtures of CO2 and H2O, their physical characteristics, and the emergence of certain characteristics depending on the method of formation.

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Section: Resultsmentioning

confidence: 52%

“…The vapor deposition method is one of the most effective methods of obtaining thin films of cryocondensates in wellcontrolled structural phase states [37][38][39]. It is also widely used to study the physical properties of compounds at low and ultra-low temperatures [39][40][41][42][43].…”

Section: Methodsmentioning

confidence: 99%

A Semi-Automatic Examination of Co2 Structures in Thin Films at Low Temperatures

Golikov,

Yerezhep,

Yerlanov

2023

ijmph

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“…The apparatus used for studying amorphous structures was partially described in a number of our previous works. , Therefore, we will not describe it in detail here. It is only worth noting that during this research, the operation of the PID controller was improved to increase its speed and speed of reaching the control temperatures, using a small program written in the LabView graphical programming environment (National Instruments, USA) …”

Section: Methodsmentioning

confidence: 99%

Analysis of Vibrational Spectra of Tetrafluoroethane Glasses Deposited by Physical Vapor Deposition

et al. 2023

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This paper presents the results obtained in the study of structural phase transitions in thin films of R134A. The samples were condensed on a substrate by physical deposition of R134A molecules from the gas phase. Structural phase transformations in samples were investigated by observing the changes in characteristic frequencies of Freon molecules in the mid-infrared range with the help of Fourier-transform infrared spectroscopy. The experiments were carried out in the temperature range from 12 to 90 K. A number of structural phase states, including glassy forms, were detected. The changes in thermogram curves at fixed frequencies of half-widths of absorption bands of R134A molecules were revealed. These changes indicate a large bathochromic shift of these bands at frequencies of ν = 842 cm–1, ν = 965 cm–1, and ν = 958 cm–1 and a hypsochromic shift of the bands at frequencies of ν = 1055 cm–1, ν = 1170 cm–1, and ν = 1280 cm–1 at temperatures from T = 80 K to T = 84 K. These shifts are related to the structural phase transformations in the samples.

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“…The following materials were used for the study: methanol, nitrous oxide, first grade nitrogen (99.999% purity) with the maximum oxygen fraction not exceeding 0.0005% and water vapor not exceeding 0.0007% (ISKHAN TEHNOGAS LLP, Almaty, Kazakhstan) GOST 9293-74, and highest-purity grade (99.993%) argon gas with the maximum oxygen fraction not exceeding 0.0007%, water vapor not exceeding 0.0007% and containing no more than 0.0005% of nitrogen (ISKHAN TEHNOGAS LLP, Almaty, Kazakhstan) GOST 10157-79. 23 …”

Section: Methodsmentioning

confidence: 99%

“… Experimental setup for cryovacuum condensation: (1) vacuum chamber, (2) vacuum pump Turbo-V-301, (3) vacuum gate valve CFF-100, (4) pressure detector FRG-700, (5) Gifford–McMahon refrigerator, (6) substrate, (7) photo multiplier, laser interferometer, (8) light source, optical channel, (9) IR spectrometer, (10) high-precision gas supply leak into the chamber; and (11) gas leak into the mixture production system. 23 …”

Section: Methodsmentioning

confidence: 99%

Infrared Analysis and Effect of Nitrogen and Nitrous Oxide on the Glass Transition of Methanol Cryofilms

et al. 2022

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Methanol plays an important role in studying the structure and dynamics of hydrogen bonds in alcohols and other physiologically important compounds in the condensed state. The physical vapor deposition method and two-beam interferometry make it possible to study the structure of polyatomic molecules, the nature and character of intermolecular interactions, and the internal structure of various compounds. Thus, it becomes possible to analyze changes in the internal structure of substances near the points of their phase transitions and glass transitions at ultralow temperatures. In this work, we have studied the effect of nitrogen and nitrous oxide on the dependence of refractive indices of methanol on temperature and on structural-phase transformations upon heating from 16 to 160 K.

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Optical Studies of Thin Films of Cryocondensed Mixtures of Water and Admixture of Nitrogen and Argon

Cited by 5 publications

References 29 publications

A Semi-Automatic Examination of Co2 Structures in Thin Films at Low Temperatures

A Semi-Automatic Examination of Co2 Structures in Thin Films at Low Temperatures

Analysis of Vibrational Spectra of Tetrafluoroethane Glasses Deposited by Physical Vapor Deposition

Infrared Analysis and Effect of Nitrogen and Nitrous Oxide on the Glass Transition of Methanol Cryofilms

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