Removal of baseline artifacts from variable-temperature diffuse reflectance infrared spectra

1992 ◽  
Vol 64 (17) ◽  
pp. 2010-2013 ◽  
Author(s):  
Robert L. White
Keyword(s):  
Infrared Spectra ◽  
Diffuse Reflectance ◽  
Variable Temperature ◽  
Diffuse Reflectance Infrared

Requirements for Thermal Analysis by Variable-Temperature Diffuse Reflectance Infrared Spectroscopy

1992 ◽  
Vol 46 (10) ◽  
pp. 1508-1513 ◽  
Author(s):  
Robert L. White
Keyword(s):  
Infrared Spectroscopy ◽  
Calcium Oxalate ◽  
Diffuse Reflectance ◽  
Variable Temperature ◽  
Calcium Oxalate Monohydrate ◽  
Quantitative Information ◽  
Center Frequency ◽  
Effect Of Temperature ◽  
Diffuse Reflectance Infrared Spectroscopy ◽  
Diffuse Reflectance Infrared

The effect of temperature on diffuse reflectance infrared spectroscopy measurements is discussed. Instrumental parameters that determine the accuracy of variable-temperature diffuse reflectance Fourier transform infrared spectroscopy (VT-DRIFTS) measurements are identified, and methods for removing baseline artifacts resulting from fluctuations in these parameters are given. Procedures for extracting structure-specific quantitative information from DRIFTS spectra acquired at different temperatures are outlined. The use of VT-DRIFTS to generate vibration-specific absorbance band intensity and center frequency temperature profiles for calcium oxalate monohydrate is described, and correlations between these profiles and the known thermal behavior of calcium oxalate monohydrate are given.

Diffuse reflectance infrared spectra of kaolinite and kaolinite/alkali halide mixtures. Curve-fitting of the OH stretching region

1991 ◽  
Vol 69 (11) ◽  
pp. 1786-1790 ◽  
Author(s):  
K. H. Michaelian ◽  
W. I. Friesen ◽  
S. Yariv ◽  
A. Nasser
Keyword(s):  
Infrared Spectra ◽  
Curve Fitting ◽  
Alkali Halide ◽  
Diffuse Reflectance ◽  
Alkali Halides ◽  
Hydroxyl Groups ◽  
Caesium Chloride ◽  
Inner Surface ◽  
Structural Hydroxyl ◽  
Diffuse Reflectance Infrared

Diffuse reflectance infrared spectra of kaolinite and binary mixtures of this clay with alkali halides have been analysed using curve-fitting and deconvolution. For caesium chloride and caesium bromide, decomposition of the hydroxyl stretching region has made it possible to correlate the positions and intensities of bands due to structural hydroxyl groups of kaolinite, or to intercalated water, with the degree of intercalation. One of these bands, arising from uncoupled inner surface OH stretching in kaolinite, is not identifiable in spectra of the uncomplexed clay or mixtures where intercalation did not occur. A new band revealed by curve-fitting spectra of intercalated samples is attributed either to water at the interface between the clay and the alkali halide, or to an FeO—H impurity in the kaolinite. Key words: kaolinite, infrared, curve-fitting.

VT-DRIFTS: A Two-Dimensional Infrared Thermal Analysis Method

1993 ◽  
Vol 47 (9) ◽  
pp. 1492-1496 ◽  
Author(s):  
Robert L. White
Keyword(s):  
Thermal Analysis ◽  
Diffuse Reflectance ◽  
Variable Temperature ◽  
Calcium Oxalate Monohydrate ◽  
Poly Vinyl Alcohol ◽  
Analysis Method ◽  
Temperature Dependent ◽  
Structure Changes ◽  
Diffuse Reflectance Infrared Spectroscopy ◽  
Diffuse Reflectance Infrared

Thermal analysis by using variable-temperature diffuse reflectance infrared spectroscopy (VT-DRIFTS) is described. Techniques for extracting spectral information from VT-DRIFTS data regarding temperature-dependent solid-state structure changes are discussed. The use of VT-DRIFTS for investigating the thermal degradation mechanisms of calcium oxalate monohydrate and poly(vinyl alcohol) and for profiling the Lewis and Brønsted acid strength distributions for an HZSM-5 zeolite by monitoring pyridine desorption as a function of temperature is described.

Effect of absorbing matrixes on diffuse reflectance infrared spectra

1986 ◽  
Vol 58 (11) ◽  
pp. 2179-2184 ◽  
Author(s):  
Paul J. Brimmer ◽  
Peter R. Griffiths
Keyword(s):  
Infrared Spectra ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Infrared

Pre-treatment of diffuse reflectance infrared spectra for quantitative analysis of macro porous polymer particles

1999 ◽  
Vol 20 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Yi-Zeng Liang ◽  
Alfred A Christy ◽  
Anne K Nyhus ◽  
Steinar Hagen ◽  
Jon-Sverre Schanche ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Infrared Spectra ◽  
Diffuse Reflectance ◽  
Porous Polymer ◽  
Polymer Particles ◽  
Pre Treatment ◽  
Diffuse Reflectance Infrared

scholarly journals Soft Mode Metal-Linker Dynamics in Carboxylate MOFs

2020 ◽  
Author(s):  
Anastasia Andreeva ◽  
Lihaokun Chen ◽  
Khoa N. Le ◽  
Michael E. Kellman ◽  
Christopher H. Hendon ◽  
...  
Keyword(s):  
Diffuse Reflectance ◽  
Variable Temperature ◽  
Negative Thermal Expansion ◽  
Melting Behavior ◽  
Zeolitic Imidazolate Frameworks ◽  
Guest Molecules ◽  
Metal Organic ◽  
The Common ◽  
New Perspective ◽  
Diffuse Reflectance Infrared

<div> <div> <div> <p>Through comprehensive analysis of carboxylate-based metal-organic frameworks (MOFs), we present general evidence for dynamic metal-linker bonding that challenges the common perception of MOF structures being static. Structural dynamics in MOFs, however, typically refers to the “breathing” behavior of pore cavities and the transient binding of guest molecules, but dynamic bonding would explain important MOF phenomena in catalysis, post- synthetic exchange, negative thermal expansion, and crystal growth. Here, we demonstrate through use of variable-temperature diffuse reflectance infrared Fourier transform spectroscopy (VT- DRIFTS) aided by ab initio plane wave density function theory, that similar evidence for melting behavior in zeolitic imidazolate frameworks (ZIFs) can be observed for carboxylate MOFs by monitoring the red-shifts of carboxylate stretches coupled to anharmonic metal-carboxylate oscillators. To demonstrate the generality of these findings, we investigate a wide class of carboxylate MOFs that includes iconic examples with diverse structures and metal-linker chemistry. As the very vibrations invoked in ZIF melting, but heretofore unobserved for carboxylate MOFs, these metal-linker dynamics resemble the ubiquitous soft modes that trigger important phase transitions in diverse classes of materials, while offering a fundamentally new perspective for the design of next-generation metal-organic materials. </p> </div> </div> </div>

Sign in / Sign up

Export Citation Format

Share Document