scholarly journals ИК спектроскопия высокого разрешения в низкотемпературных матрицах. Структура фундаментальных полос поглощения SiH-=SUB=-4-=/SUB=- в азотной и аргоновой матрицах

2020 ◽  
Vol 128 (10) ◽  
pp. 1478
Author(s):  
Р.Е. Асфин ◽  
М.В. Бутурлимова ◽  
Т.Д. Коломийцова ◽  
И.К. Тохадзе ◽  
К.Г. Тохадзе ◽  
...  
Keyword(s):  
High Resolution ◽  
Low Temperature ◽  
Gas Phase ◽  
Experimental Conditions ◽  
Bending Vibration ◽  
Argon Matrix ◽  
Solid Nitrogen ◽  
The Matrix ◽  
Stretching Vibration ◽  
Narrow Bands

The features of high resolution IR spectra of the SiH4 molecule in N2 and Ar low-temperature matrices at 6.6-20 K were analyzed depending on experimental conditions. It was found, that in the nitrogen matrix in region of stretching vibration of 28SiH4 three narrow bands are observed, in the region of bending vibration (ν4) two bands are observed instead of one, which is explained by a change in the symmetry of the molecule from Td in the gas phase to C3v in solid nitrogen. In the argon matrix spectra change even more, where, in addition to narrow bands, the broad enough components are also recorded. The calculations of the SiH4 spectrum in the Ar matrix were performed based on the QM/MM approach, which confirm the reality of the change in the symmetry of the molecule as a result of its interaction with the matrix environment.

High Resolution Infrared Detection of O=PF in the Gas Phase

1999 ◽  
Vol 54 (8-9) ◽  
pp. 507-512 ◽  
Author(s):  
P. Paplewski ◽  
H. Bürger ◽  
H. Beckers
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Gas Phase ◽  
Ground State ◽  
Infrared Detection ◽  
Centrifugal Distortion ◽  
Perfect Agreement ◽  
The Matrix ◽  
Centrifugal Distortion Constants ◽  
Matrix Ir Spectra

Short-lived phosphenous fluoride, 0=PF, has been made by flash pyrolysis of F2POPF2 in Ar at 1200°C and detected by gas phase IR spectroscopy. The υ1 band, υ0 = 1297.5372 cm-1 , has been studied with a resolution of 8 x 10-3 cm-1 , and about 1500 transitions have been assigned. These were fitted using a Watson-type Hamiltonian, σ = 1.5 x 10-3 cm-1 , to excited state parameters up to quartic centrifugal distortion constants. The υ2 band was located at 819.58 cm-1 . An extended set of ground state parameters was obtained by combining recently measured microwave transitions with ground state combination differences formed from υ1 transitions. The experimental results are in perfect agreement with the matrix IR spectra, mw measurements and ab initio calculations but disagree with a recently claimed low resolution detection of OPF in the gas phase.

HIGH-RESOLUTION, LOW-TEMPERATURE PHOTOEMISSION SPECTROSCOPY AT THE HISOR LINEAR UNDULATOR BEAMLINE

2002 ◽  
Vol 09 (01) ◽  
pp. 529-534 ◽  
Author(s):  
KENYA SHIMADA ◽  
MASASHI ARITA ◽  
YUKIHARU TAKEDA ◽  
HIROYUKI FUJINO ◽  
KENICHI KOBAYASHI ◽  
...  
Keyword(s):  
High Resolution ◽  
Low Temperature ◽  
Gas Phase ◽  
Photon Energy ◽  
Energy Resolution ◽  
Electronic States ◽  
Photon Flux ◽  
Photoemission Spectroscopy ◽  
Resonant Photoemission ◽  
Photoemission Study

In order to study the electronic states of solids, using high-resolution, low-temperature photoemission spectroscopy (PES) with tunable photon energies, we have constructed a high-resolution undulator beamline operating in the photon-energy range 26–300 eV at the compact 700 MeV electron-storage ring HiSOR located at Hiroshima University. By way of gas-phase experiments, with photon flux larger than 2 × 1010 photons/s, photon-energy resolving powers of E/ΔE > 16000 and 3800 were obtained at hν ~ 48 eV and ~ 244 eV, respectively. High-resolution PES experiments on evaporated Au at 8 K were performed at the beamline with a total energy resolution of ΔE = 12 meV at hν = 48 eV. Among the first experiments from the beamline, a resonant photoemission study of UNiSn is presented. The U 5f derived peak is significantly enhanced at hν = 98 eV.

Hydrogen bonding in the gas phase: the infrared spectra of complexes of hydrogen fluoride with hydrogen cyanide and methyl cyanide

1971 ◽  
Vol 325 (1560) ◽  
pp. 133-149 ◽  
Keyword(s):  
Hydrogen Bond ◽  
Fine Structure ◽  
Gas Phase ◽  
Infrared Spectra ◽  
Low Frequency ◽  
Bending Vibration ◽  
Methyl Cyanide ◽  
Complete Assignment ◽  
Stretching Vibration ◽  
The Individual

The infrared spectra of the gas phase complexes HCN-HF, DCN-DF and four isotopic species of CH3CN-HF have been measured over the range 200 to 4000 cm -1 . Two bands have been observed, one associated with the stretching vibration of HF in the complex and the other with a bending vibration of the hydrogen bond itself. At higher resolution both bands show fine structure which has been interpreted as being a series of hot bands associated with transitions from excited levels of another low-frequency bending vibration of the hydrogen bond. In the first band the peaks are P branch bandheads in the individual hot bands and in the second band they are sharp Q branches. From temperature studies of these bands and from the effects of isotopic substitution on the spacing of the fine structure the frequency of the lower bending vibration has been determined. Further structure in the first band gives the frequency of the stretching vibration of the hydrogen bond itself. A complete assignment of all the vibrations associated with the hydrogen bond has therefore been made. From the frequencies of the two bending motions (555 and 70 cm -1 for the HCN-HF complex) values of the bending force constants have been calculated. Several anharmonic constants have also been measured and the effect of anharmonicity on the breadth of bands associated with the hydrogen bond is discussed.

The infrared matrix isolation spectra of ND3 and NH3 in an argon matrix in the v2 bending region

1978 ◽  
Vol 31 (2) ◽  
pp. 247 ◽  
Author(s):  
JA Cugley ◽  
S Liberts ◽  
ADE Pullin
Keyword(s):  
Gas Phase ◽  
Matrix Isolation ◽  
Phase Model ◽  
Fundamental Region ◽  
Fractional Change ◽  
Argon Matrix ◽  
Rotational Constants ◽  
A Value ◽  
The Matrix

The spectra of NH3 and ND3 in an argon matrix have been obtained in the v2 (bending fundamental) region. The v2 region of ND3 has been interpreted in terms of a gas-phase model, with slightly altered rotational constants. Thus for the matrix an effective value of (B'+B') = 9.85 is required compared with 10.25 cm-1 for the gas phase. This represents a smaller fractional change than for NH3. The inversion splitting of ND3 in the argon matrix has been clearly resolved and a value of 2.0�0.1 cm-1 deduced. However, there are extra lines in the spectrum of ND3 which we cannot assign on the basis of a gas-phase model. For NH3 some vib-rotor 'lines' have been shown to be composite, in particular Q(11+) and Q(11-) are close triplets.

Infrared Spectroscopic Study of Ammonia – Sulfur Dioxide – Water Solid State System

1975 ◽  
Vol 53 (17) ◽  
pp. 2646-2656 ◽  
Author(s):  
I.C. Hisatsune ◽  
Julian Heicklen
Keyword(s):  
Solid State ◽  
Sulfur Dioxide ◽  
Low Temperature ◽  
Solid State Reactions ◽  
Infrared Spectroscopic Study ◽  
Experimental Conditions ◽  
Vibrational Assignments ◽  
The Matrix ◽  
Ammonium Sulfite ◽  
Infrared Window

Products formed during the solid state reactions between ammonia and sulfur dioxide in the presence or absence of water have been investigated by infrared spectroscopy. Warming of a low-temperature matrix of SO2 with excess NH3 produces (NH3)2•SO2 at −90 °C. This adduct decomposes near −50 °C into NH3•SO2 which has a yellow color. With excess SO2 only NH3•SO2 appears at −150 °C. The 1:1 complex disappears from the low-temperature infrared window at about −20 °C. With H2O present in the matrix, (NH3)2•SO2 is converted at −80 °C into ammonium sulfite which is stable to room temperature where it can be pumped off readily from the infrared window. With less than the stoichiometric amount of water, the final product of the warming sequence is ammonium pyrosulfite whose infrared spectrum varies considerably with experimental conditions. The pyrosulfite reacts further with water to give ammonium bisulfite. The infrared spectra of solid ammonium bisulfite and perdeuteroammonium bisulfite show that the hydrogen in the bisulfite ion is bonded to the sulfur atom. Vibrational assignments have been made for all the compounds.

Electrolytic Isolation of Twin-Type Shock Deformation Structures

1967 ◽  
Vol 25 ◽  
pp. 318-319
Author(s):  
F. I. Grace ◽  
L. E. Murr
Keyword(s):  
Grain Boundaries ◽  
Thin Foil ◽  
Electrolyte Composition ◽  
Experimental Conditions ◽  
Average Current Density ◽  
Electron Transmission ◽  
Deformation Structures ◽  
The Matrix ◽  
Average Current ◽  
Specimen Edge

During the course of electron transmission investigations of the deformation structures associated with shock-loaded thin foil specimens of 70/30 brass, it was observed that in a number of instances preferential etching occurred along grain boundaries; and that the degree of etching appeared to depend upon the various experimental conditions prevailing during electropolishing. These included the electrolyte composition, the average current density, and the temperature in the vicinity of the specimen. In the specific case of 70/30 brass shock-loaded at pressures in the range 200-400 kilobars, the predominant mode of deformation was observed to be twin-type faults which in several cases exhibited preferential etching similar to that observed along grain boundaries. A novel feature of this particular phenomenon was that in certain cases, especially for twins located in the vicinity of the specimen edge, the etching or preferential electropolishing literally isolated these structures from the matrix.

scholarly journals Development and Application of a Novel Pluri-Residue Method to Determine Polar Pesticides in Fruits and Vegetables through Liquid Chromatography High Resolution Mass Spectrometry

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 553
Author(s):  
Lorena Manzano-Sánchez ◽  
José Antonio Martínez-Martínez ◽  
Irene Domínguez ◽  
José Luis Martínez Vidal ◽  
Antonia Garrido Frenich ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
High Resolution ◽  
High Performance ◽  
Fruits And Vegetables ◽  
High Resolution Mass Spectrometry ◽  
Stationary Phases ◽  
Mean Values ◽  
Polar Pesticides ◽  
Relative Standard ◽  
The Matrix

Nowadays, highly polar pesticides are not included in multiresidue methods due to their physico-chemical characteristics and therefore, specific analytical methodologies are required for their analysis. Laboratories are still looking for a pluri-residue method that encompasses the largest number of polar pesticides. The aim of this work was the simultaneous determination of ethephon, 2-hydroxyethylphosphonic acid (HEPA), fosetyl aluminum, glyphosate, aminomethylphosphonic acid (AMPA), N-acetyl-glyphosate and N-acetyl-AMPA in tomatoes, oranges, aubergines and grapes. For that purpose, an ultra high performance liquid chromatography (UHPLC) coupled to a high resolution single mass spectrometer Orbitrap-MS were used. Different stationary phases were evaluated for chromatographic separation, and among them, the stationary phase Torus DEA provided the best separation of the selected compounds. The QuPPe method was used for the extraction of the analytes, but slight modifications were needed depending on the matrix. The developed method was validated, observing matrix effect in all matrices. Intra- and inter-day precision were estimated, and relative standard deviation were lower than 19%. Recoveries were satisfactory, and mean values ranged from 70% to 110%. Limits of quantification were between 25 and 100 µg kg−1. Finally, the analytical method was applied to different fruits and vegetables (oranges, tomatoes, aubergines and grapes).

Transition Insulator-Metal and Antiferromagnetic-Paramagnetic Cu Doped in La0.47Ca0.53MnO3

2015 ◽  
Vol 1123 ◽  
pp. 73-77 ◽  
Author(s):  
Yohanes Edi Gunanto ◽  
K. Sinaga ◽  
B. Kurniawan ◽  
S. Poertadji ◽  
H. Tanaka ◽  
...  
Keyword(s):  
High Resolution ◽  
Low Temperature ◽  
Magnetic Structure ◽  
Room Temperature ◽  
Paramagnetic Phase ◽  
Perovskite Manganites ◽  
Antiferromagnetic Phase ◽  
Temperature Transition ◽  
Cu Doping ◽  
Metal State

The study of the perovskite manganites La0.47Ca0.53Mn1-xCuxO3 with x = 0, 0.06, 0.09, and 0.13 has been done. The magnetic structure was determined using high-resolution neutron scattering at room temperature and low temperature. All samples were paramagnetic at room temperature and antiferromagnetic at low temperature. Using the SQUID Quantum Design, the samples showed that the doping of the insulating antiferromagnetic phase La0.47Ca0.53MnO3 with Cu doping resulted in the temperature transition from an insulator to metal state, and an antiferromagnetic to paramagnetic phase. The temperature transition from an insulator to metal state ranged from 23 to 100 K and from 200 to 230 K for the transition from an antiferromagnetic to paramagnetic phase.

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