This review reports the recent progress on ATR-far ultraviolet (FUV) spectroscopy in the condensed phase. ATR-FUV spectroscopy for liquids and solids enables one to explore various topics in physical chemistry, analytical chemistry, nanoscience and technology, materials science, electrochemistry, and organic chemistry. In this review, we put particular emphasis on the three major topics: (1) studies on electronic transitions and structures of various molecules, which one cannot investigate ordinary UV spectroscopy.
View Article and Find Full Text PDFAlthough determining the chemical states of salts and ions is critical in numerous fields, such as elucidating biological functions and maintaining food quality, the current direct observation methods are insufficient. We propose a spectral analysis method of directly observing the phase transitions of NaCl solutions using the changes in the charge-transfer-to-solvent band and the absorption band representing the first electron transition (Ã ← X̃) of HO. The intensities of these bands may be observed using attenuated total reflection far-ultraviolet spectroscopy.
View Article and Find Full Text PDFInter- and intramolecular hydrogen bonding and their temperature-dependent changes in a poly(4-vinylphenol)/poly(methyl methacrylate)(PVPh 30%/PMMA 70%) blend were investigated using near-infrared (NIR) and infrared (IR) spectroscopy. Band assignments of the fundamentals and first overtones of the OH stretching mode of a free OH group and OH groups in C=O···HO and OH···OH (dimer, trimer, and oligomer) hydrogen bonding of PVPh 30%/PMMA 70% were carried out by comparison between its NIR and IR spectra and comparison with NIR and IR spectra of phenol. The comparison of the NIR spectra of the PVPh 30%/PMMA 70% blend (hereafter, we denote it as PVPh30%) with the corresponding IR spectra reveals that to observe bands arising from the free OH and OH···OH dimer, which is a weaker hydrogen bonding, NIR is better while to investigate bands originating from OH groups in the OH···O=C and OH···OH (oligomer) hydrogen bonds, which are stronger hydrogen bonding, IR is better.
View Article and Find Full Text PDFThe demand for Li secondary batteries is increasing, with the need for batteries with a higher level of performance and improved safety features. The use of a highly concentrated aqueous electrolyte solution is an effective way to increase the safety of batteries because it is possible to use "water-in-salt" (WIS) and "hydrate-melt" (HM) electrolytes for practical applications. These electrolytes exhibit a potential window of >3.
View Article and Find Full Text PDFAttenuated total reflection far-ultraviolet (ATR-FUV) spectra in the 145-250 nm region were studied for four kinds of proteins (two α-helix-rich proteins: bovine serum albumin (BSA) and lysozyme and two β-sheet rich proteins: concanavalin A and γ-globulin) in different solutions (pure water and phosphate buffered saline, or PBS) with different concentrations. All the spectra show a band at 191 nm due to the π-π transition of amide bonds of the proteins. The wavelength of the band does not change with their second structures, suggesting that the corresponding electronic transition mode is localized and polarized in the direction that is not affected by the difference in the peptide folding.
View Article and Find Full Text PDFThis work provides new insight into assembling of phenol in various solvents and competition between different kinds of interactions. To examine both weak and strong interactions, we selected a series of non-aromatic and aromatic solvents. Infrared spectra were measured at low (0.
View Article and Find Full Text PDFNear-infrared (NIR) spectra of phenol in a series of non-aromatic and aromatic solvents were recorded to study the competition between various types of solute-solute and solute-solvent interactions. Depending on the phenol concentration, the free OH and OH involved in the OH⋯OH interactions in the dimers and higher associates are present in cyclohexane solutions. On the other hand, free OH does not appear in Cl-containing solvents since at a low phenol content the OH groups participate in the OH⋯Cl interactions.
View Article and Find Full Text PDFFar-ultraviolet (FUV) spectra were measured for cyclohexane, methyl cyclohexane, six isomers of dimethyl cyclohexane, and - and -decalin. Attenuated total reflection-FUV (ATR-FUV) spectroscopy, which we originally proposed, provides systematic information about the excitation states of saturated organic molecules and the hyperconjugation of σ bonds. The FUV spectra of cyclohexane and methyl cyclohexane in neat liquids showed a band with central wavelengths near 155 and 162 nm.
View Article and Find Full Text PDFThe purpose of this review is to demonstrate advances, challenges and perspectives of quantum chemical approaches in molecular spectroscopy of the condensed phase. Molecular spectroscopy, particularly vibrational spectroscopy and electronic spectroscopy, has been used extensively for a wide range of areas of chemical sciences and materials science as well as nano- and biosciences because it provides valuable information about structure, functions, and reactions of molecules. In the meantime, quantum chemical approaches play crucial roles in the spectral analysis.
View Article and Find Full Text PDFIn this study, we explored the electronic structure of the surfaces of polyethylene samples having different crystallinities using attenuated total reflection (ATR) far-ultraviolet (FUV) spectroscopy and quantum chemical calculations. Specifically, the ATR-FUV spectra of five types of high-density polyethylene (HDPE), six types of linear low-density PE (LLDPE), and seven types of low-density PE (LDPE) were obtained. All the spectra contained an intense band near 156 nm and a broad band between 180 and 190 nm.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
May 2021
Far-ultraviolet (FUV) spectroscopy in the region of 140-200 nm of condensed-phase has received keen interest as a new electronic spectroscopy. The introduction of the attenuated total reflection (ATR) technique to the FUV region has opened a new avenue for FUV spectroscopy of liquids and solids. ATR-FUV spectroscopy enables the study of electronic structures and transitions of most types of molecules.
View Article and Find Full Text PDFPrevious measurements of fundamental, first-, second- and third overtones of the OH-stretching vibration of phenol and 2,6-difluoro-phenol by use of visible (Vis), near-infrared (NIR) and infrared (IR) spectroscopy revealed an oscillating pattern in the intensity quotient between the two kinds of solvents, carbon tetrachloride and n-hexane, upon increase of the vibrational quantum number, which could not be reproduced utilizing quantum mechanical calculations in implicit solvation. In the present study this phenomenon was successfully explained for the first time, employing an explicit consideration of solute-solvent interactions in combination with modern grid-based methods to solve the time-independent Schrödinger equation. The capabilities of this framework of (i) not requiring any assumptions on the form of the resulting wave function, (ii) focusing the description on the vibrational mode of interest and (iii) taking solute-solvent interactions explicitly into account are a particularly lucid example of the advantages in applying state-of-the-art approaches in investigations of challenging vibrational quantum problems.
View Article and Find Full Text PDFThis present research applied the ATR-FTIR technique and principle component analysis (PCA) to investigate molecular surface changes in pre-carbonized solid biomass, called Kindai Bio-coke (BIC) and Japanese cedar. The product is utilized as an alternative to coal coke in the cupola furnace in the steel industry in order to reduce CO emissions. The aim is to explore key elements for improving the BIC product applications from the fundamental molecular scale by using PCA to distinguish between changes during the BIC transformation and the differences in BIC samples.
View Article and Find Full Text PDFAttenuated total reflectance-far ultraviolet (ATR-FUV) spectra of Li and polyether ligands, such as glymes and poly (ethylene glycol) (PEG), in solution give information about changes in the electronic states of the ligands. From the ATR-FUV spectra, the coordination numbers between Li and monoglyme, diglyme, triglyme, and PEG400 were determined to be 4, 5, 6, and 5, respectively. Our results indicate that Li is coordinated only by the ligands rather than its counter-ions.
View Article and Find Full Text PDFThis study investigates the electronic transitions of complexes of lithium with polyethylene glycol (PEG) by the absorption bands of solvent molecules via attenuated total reflectance spectroscopy in the far-UV region (ATR-FUV). Alkali-metal complexes are interesting materials because of their functional characteristics such as good ionic conductivity. These complexes are used as polymer electrolytes for Li batteries and as one of the new types of room-temperature ionic liquids, termed solvation ionic liquids.
View Article and Find Full Text PDFWe investigated the surface (<50 nm) of poly(3-hydroxybutyrate) (PHB) and its nanocomposite with graphene by attenuated total reflection far- and deep-ultraviolet (ATR-FUV-DUV; 145-300 nm; 8.55-4.13 eV) spectroscopy and quantum mechanical calculations.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
May 2018
We measured the attenuated total reflectance-far ultraviolet (ATR-FUV) spectra of poly(ethylene glycol) (PEG; average molecular weights of 200, 300, and 400) and related materials in the liquid state in the 145-200-nm wavelength region. For appropriately assigning the absorption bands, we also performed theoretical simulation of the unit-number dependent electronic spectra. The FUV spectra of PEGs contain three bands, which are assigned to the transitions between n(CHOCH)-3s Rydberg state (176 nm), n(CHOCH)-3p Rydberg state (163 nm), and n(OH)-3p Rydberg state (153 nm).
View Article and Find Full Text PDFVisible (Vis), near-infrared (NIR) and IR spectra in the 15,600-2500cm region were measured for methanol, methanol-d, and t-butanol-d in n-hexane to investigate effects of intermolecular interaction on absorption intensities of the fundamental and the first, second, and third overtones of their OH stretching vibrations. The relative area intensities of OH stretching bands of free and hydrogen-bonded species were plotted versus the vibrational quantum number using logarithm plots (V=1-4) for 0.5M methanol, 0.
View Article and Find Full Text PDFAttenuated total reflection (ATR) spectra, which are often used in IR analysis, can be transformed into extinction and refraction spectra by Kramers-Kronig transformation (KKT) with Fresnel equations. However, it is often difficult to obtain correct optical indices due to the inherent instrumental functions. This paper proposes a simple practical method for correction of KKT with two parameters, which include all the effects of the instrumental function.
View Article and Find Full Text PDFIntermolecular interactions between alkyl chains such as CH···HC should be reflected in the phase behavior of organic compounds. We measured the attenuated total reflectance spectra in the far-UV region (145-300 nm) of -tetradecane ( = 5.9 °C), through both cooling and heating, from 15 to -38 °C, to determine its temperature dependency.
View Article and Find Full Text PDFElectronic absorption spectra of imidazolium-based ionic liquids were studied by far- and deep-ultraviolet spectroscopy and quantum chemical calculations. The absorption spectra in the 145-300 nm region of imidazolium-based ionic liquids, [Cnmim](+)[BF4](-) (n = 2, 4, 8) and [C4mim](+)[PF6](-), were recorded using our original attenuated total reflectance (ATR) system spectrometer. The obtained spectra had two definitive peaks at ∼160 and ∼210 nm.
View Article and Find Full Text PDFThe first electronic transition (Ã ← X̃) of liquid water (H2O and D2O) on an α-alumina substrate was studied using variable angle attenuated total reflection far-ultraviolet (VA-ATR-FUV) spectroscopy in the wavelength region 140-180 nm (8.86-6.89 eV).
View Article and Find Full Text PDFA low temperature in situ Raman spectroscopic method was developed for the detection of unstable intermediates in electro-organic chemistry. It was effective for monitoring the generation of ArS(ArSSAr)(+) by the electrochemical oxidation of ArSSAr (Ar = p-FC6H4) in Bu4NBF4/CH2Cl2 at 195 K. The intensity of a Raman band at 427 cm(-1), which is attributable to the S-S vibration of ArS(ArSSAr)(+), increased with an increase in the electricity until 2/3 F of the electricity was consumed, whereas decreased with a further increase in the electricity indicating the decomposition of ArS(ArSSAr)(+).
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