Journal ArticleDOI
What is the Origin of Positional Fluctuation of Spectral Features: True Frequency Shift or Relative Intensity Changes of Two Overlapped Bands?
TLDR
It was found that principal component analysis (PCA) is a surprisingly sensitive tool to distinguish the two possible mechanisms of peak maximum shift.Abstract:
We investigated what is really meant by so-called positional or frequency fluctuation of spectral features. To show the difference between the true frequency shift of a single band and apparent peak maximum shift caused by relative intensity changes of overlapped adjacent bands, we analyzed infrared (IR) spectra of the OH stretching band of ethylene glycol during the heating process and the C=O stretching band of acetone in a mixed solvent CHCl(3)/CCl(4) with varying solvent compositions. These spectra are well-known examples of so-called "band shift" phenomena often interpreted as the manifestation of gradual changes in the IR frequency associated with a specific chemical bond under the influence of molecular interactions. Analyses of IR spectra showed that the apparent positional shifts of peak maxima in these systems are actually due to relative contribution changes of two overlapped bands, instead of the gradual frequency shift of a single band induced by the change in the strength of molecular interactions. To further clarify our interpretation of "peak maximum shifts", we also analyzed simulated spectral datasets, comparing the true band frequency shift and change in the relative contributions of overlapped bands. It was found that principal component analysis (PCA) is a surprisingly sensitive tool to distinguish the two possible mechanisms of peak maximum shift. The new insight revealed by this study should help the interpretation of molecular interactions probed by vibrational spectroscopy.read more
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Close-up view on the inner workings of two-dimensional correlation spectroscopy
TL;DR: The role of external perturbation in 2D correlation spectroscopy and the importance of clearly defining the observation interval of data collection are discussed in this article, and the underlying concept of synchronicity based on phase relationship is described for simple sinusoidal signals and for generalized waveforms without heavily relying on mathematical formalism.
Journal ArticleDOI
Frontiers of Two-Dimensional Correlation Spectroscopy. Part 1. New concepts and noteworthy developments
TL;DR: A comprehensive survey of new and noteworthy developments in the field of 2D correlation spectroscopy during the last four years is presented in this paper, which covers books, proceedings, and review articles published in the literature.
Journal ArticleDOI
Glucose induced variation of water structure from temperature dependent near infrared spectra
TL;DR: In this article, the structural variation of water with concentration and temperature was investigated using temperature dependent near infrared (NIR) spectra of glucose solutions following the concept of aquaphotomics and the results obtained using terahertz (THz) spectroscopy.
Journal ArticleDOI
Insights into aqueous carbofuran removal by modified and non-modified rice husk biochars.
TL;DR: Steam-activated rice husk biochar can be highlighted as a promising low-cost sustainable material for aqueous carbofuran removal as well as a potential sorbent for removal of frequently detected pesticides in water.
Journal ArticleDOI
Synthesis and characterization of Zinc/Chitosan-Folic acid complex.
Subhani Bandara,Codi anne Carnegie,Chevaun Johnson,Feyisayo Akindoju,Ebonee Williams,Julia M. Swaby,Aderemi Oki,Laura Carson +7 more
TL;DR: A chitosan derivative is synthesized that is composed of both folic acid and zinc and may serve as a viable component of a drug delivery system.
References
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Hydrogen bonding in polymers. 4. Infrared temperature studies of a simple polyurethane
TL;DR: Etude d'un polyurethanne lineaire semi-cristallin, aliphatique le polybutylene-1,4 hexamethylenecarbamate as discussed by the authors.
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Hydrogen bonding in polymers: infrared temperature studies of an amorphous polyamide
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Hydrogen bonding in polymers. 2. Infrared temperature studies of nylon 11
TL;DR: Les resultats d'etudes precedentes sur les polyamides amorphes sont applicables a ce polymere semi-cristallin this paper, i.e.
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Hydrogen bonding and the cryoprotective properties of glycerol/water mixtures.
TL;DR: The ability of Glycerol/water mixtures to inhibit ice crystallization is linked to the concentration of glycerol and the hydrogen bonding patterns formed by these solutions, which mimic the strong hydrogen bonding pattern seen in ice, yet crystallization does not occur.
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Infrared temperature studies of a simple polyurea
TL;DR: In this article, infrared temperature studies of a polyurea formed from 2-methylpentane-1,5-diamine and 4,4′-methylenebis(phenyl isocyanate) are presented.