Polarized overtone-combination bands in the near-infrared spectra of K2SnCl4•H2O and KSnCl3•H2O at cryogenic temperatures

1986 ◽  
Vol 64 (5) ◽  
pp. 1012-1019 ◽  
Author(s):  
Ian M. Walker ◽  
Paul J. McCarthy
Keyword(s):  
Water Molecule ◽  
Normal Mode ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Water Molecules ◽  
Site Symmetry ◽  
Cryogenic Temperatures ◽  
Near Infrared Spectra ◽  
Combination Bands ◽  
Anharmonicity Constants

The near-infrared (nir) spectra of K2SnCl4•H2O and KSnCl3•H2O contain many highly polarized absorptions, due largely, if not completely, to combinations of vibrations of the water molecules in the crystals. The polarization of the absorptions can be related to the site symmetry of the water molecule. In K2SnCl4•H2O combination bands based on rocking, wagging, and twisting librations are seen, from which it is possible to definitively identify the rocking libration. The librations are much less in evidence in the spectra of KSnCl3•H2O. Sets of normal mode anharmonicity constants have been calculated from the energies of the absorptions.

scholarly journals Water Adsorption Properties of Free and Dehydrated β-Cyclodextrin Studied by near Infrared Spectroscopy and Gravimetry

2016 ◽  
Vol 689 ◽  
pp. 143-147 ◽  
Author(s):  
Alfred A. Christy
Keyword(s):  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Water Adsorption ◽  
Near Infrared ◽  
Adsorption Properties ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
Near Infrared Spectra ◽  
Adsorption Of Water

β-cyclodextrin, like other carbohydrates has a tendency to adsorb water molecules and the properties are attributed to the hydroxyl groups in the molecules. β-cyclodextrin, the cyclic oligomer of glucose has a hydrophobic interior and hydrophilic exterior. The cyclic structure favours the formation of hydrogen bonds between the OH groups on the adjacent glucose units and affects the formation of hydrogen bonds with water molecules. The hydoxyl groups engaged in hydrogen bondings can be eliminated at high temperatures and the adsorption properties of the dehydrated β-cyclodextrin will depend on the new functional groups formed. The aim of the report is to discuss the issue of the water adsorption properties of free and dehydrated β-cyclodextrin. Dry β-cyclodextrin and dehydrated β-cyclodextrin at temperatures 250, 300 and 350 °C were allowed to adsorb water from a humidity controlled air environmennt and the evolving near infrared spectra were measured using a near infrared spectrometer equipped with a transflectance accessory. The near infrared spectra in the region 10,000-4000 cm-1 and their second and fourth derivative profiles were used in studying the variation in the adsorption characteristics of dehydrated β-cyclodextrin. The results of the analyses show that the adsorption of water by β-cyclodextrin decreses at 300 °C compared to 200 and 250 °C. Dehydration forms more of the ethereal type-O-bonds in the molecule and explains the decrease in the water molecular adsorption at higher dehydration temperatures.

scholarly journals Discrimination of mineral waters using near infrared spectroscopy and aquaphotomics

2014 ◽  
Vol 68 (2) ◽  
pp. 257-264 ◽  
Author(s):  
Jelena Muncan ◽  
Lidija Matija ◽  
Jovana Simic-Krstic ◽  
Srecko Nijemcevic ◽  
Djuro Koruga
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Dynamic Properties ◽  
Mineral Waters ◽  
Molecular Organization ◽  
Human Organism ◽  
Water Molecules ◽  
Near Infrared Spectra ◽  
Healthy Functioning

Despite that water is one of the most studied materials today its dynamic properties are still not well understood. Water state in human organism is of high importance for normal healthy functioning of human body. Different kinds of water are usually classified according to its present solutes, and concentrations of these solutes, but though it is known that water molecules can form clusters around present solutes, classification of waters based on types of water molecular organization and present clusters is not present in current literature. In this study we used multivariate analysis for classification of commercial mineral waters based on their near infrared spectra (NIR). Further, we applied Aquaphotomics, a new approach for interpretation of near infrared spectra of water, which gives insight into organization of water molecules in each of these waters.

HYDROGEN BONDING IN THE AMINE HYDROHALIDES: III. NEAR-INFRARED SPECTRA OF ALIPHATIC AMINE HYDROHALIDES

1960 ◽  
Vol 38 (10) ◽  
pp. 1901-1910 ◽  
Author(s):  
P. Sauvageau ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bonding ◽  
Secondary Amine ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Potential Surface ◽  
Aliphatic Amine ◽  
Bending Vibrations ◽  
Near Infrared Spectra ◽  
Combination Bands

The first overtones of the [Formula: see text] stretching fundamentals are very weak and difficult to locate. Binary combinations between [Formula: see text] stretching and [Formula: see text] bending vibrations and also [Formula: see text] stretching–bending combinations fall into the 4600–4400 cm−1 area for primary and secondary amine hydrohalides and are much stronger. The intensity of these combination bands is not due to the anharnionicity of the potential surface but to the electrical anharmonicity of bending vibrations.

The near-infrared spectra of some simple aldehydes

1970 ◽  
Vol 48 (23) ◽  
pp. 3694-3703 ◽  
Author(s):  
G. Lucazeau ◽  
C. Sandorfy
Keyword(s):  
Liquid Nitrogen ◽  
Infrared Spectra ◽  
Solvent Effects ◽  
Near Infrared ◽  
Fermi Resonance ◽  
Near Infrared Spectra ◽  
Anharmonicity Constants

The near-infrared spectra of CH3CHO, CD3CHO, CH3CDO, CF3CHO, CHCl2CHO, and CCl3CHO were measured from 4000 to 9000 cm−1 in solution at room and liquid nitrogen temperatures. Assignments are made and cases of Fermi resonance are examined. A few potential and anharmonicity constants are obtained. Solvent effects affecting fundamentals and overtones are discussed.

Measurement of the Near-Infrared Spectra of H2O-SiOH-Bearing Siliceous Materials at High Pressures

1979 ◽  
Vol 33 (5) ◽  
pp. 495-499 ◽  
Author(s):  
Klaus Langer ◽  
Werner A. P. Luck ◽  
Otto Schrems
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
High Pressures ◽  
Band System ◽  
High Energy ◽  
Single Beam ◽  
Near Infrared Spectra ◽  
Diamond Anvil ◽  
Combination Bands ◽  
Energy Components

Techniques for measuring OH-combination bands of water and other OH-group bearing solid or liquid materials in the near-infrared (6000 to 4000 cm−1) at high pressures by means of a modified diamond anvil cell, adapted to a single beam micro-spectrometer, have been developed and applied to opals, i.e., minerals in the system SiO2-H2O containing relatively high amounts of water and SiOH. Liquid embedding, using the gasket technique and poly-fluoro-carbon oils as embedding liquids, which provide a hydrostatic pressure environment at least up to 50 kbar, is applied for solid materials. The high pressure near-infrared spectra of gel-like, spherulitic opal-AG show a strong relative decrease of the high energy components of the complex (v1 + v2)H2O-band system at around 5200 cm−1 in favor of the low energy components of this band system. This is tentatively interpreted as due to an increase of fully hydrogen bonded water at the expense of water in which only one OH-group is H-bonded. The corresponding effect in opal-AN with a glass-like continuous SiO4/2-tetrahedral network is much smaller.

scholarly journals Comparison of adsorption properties of commercial silica and rice husk ash (RHA) silica: A study by NIR spectroscopy

2021 ◽  
Vol 19 (1) ◽  
pp. 426-431
Author(s):  
Alfred A. Chirsty ◽  
Pathmanathan Sivarukshy
Keyword(s):  
Silica Gel ◽  
Rice Husk ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Rice Husk Ash ◽  
Adsorption Properties ◽  
Water Molecules ◽  
Silanol Groups ◽  
Near Infrared Spectra ◽  
Adsorption Of Water

Abstract Adsorption properties of Silica gel (commercial silica), rice husk ash (RHA) silica, and their hydrothermally treated products towards water molecules were studied in this work. RHA silica was prepared by heating rice husk to 650°C for 4 h after pretreatment with hydrochloric acid. Portions of the samples of silica were evacuated at 200℃ and then allowed to adsorb water molecules from the surrounding air at either 42 or 50% humidity. The near infrared spectra of these samples were measured at different time intervals during their adsorption of water molecules. The evolved near infrared spectra were analyzed using second derivative techniques. Adsorption properties of these samples were further studied by gravimetric analysis. Surface functionalities and adsorption evolution of water molecules on silica samples studied showed that the adsorption of water molecules on commercial silica gel sample and RHA silica Samples takes place readily with hydrogen-bonded silanol groups on the surfaces of the samples. This adsorption arising from the OH stretching and bending vibrations of these water molecules gives rise to a band at 5,270 cm−1 in the near infrared region. The adsorbed water molecules then continue at the free silanol groups which is indicated by the absorption around 5,314 cm−1. The results clearly show that the silica made from rice husk adsorb water in the same manner as the commercial silica, but the quantity of water molecules adsorbed is less compared to commercial silica used in this experiment. However, the study clearly shows that the rice husk silica can replace the commercial silica as a substitute for desiccant purposes in industry.

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