Étude du spectre d'absorption du méthane 13CD4 dans la region de 1000 cm−1 analyse de la diade ν2/ν4

1988 ◽  
Vol 66 (7) ◽  
pp. 622-629 ◽  
Author(s):  
G. Pierre ◽  
G. Millot ◽  
A. Valentin ◽  
L. Henry ◽  
B. Foy ◽  
...  
Keyword(s):  
Ground State ◽  
Full Width Half Maximum ◽  
Experimental Spectrum ◽  
Effective Hamiltonian ◽  
Order Of Approximation ◽  
Vibrational States ◽  
The Fourier Transform ◽  
Hamiltonian Parameters ◽  
Fifth Order ◽  
Better Than

The Fourier transform absorption spectrum of 13CD4 methane has been recorded from 924 to 1190 cm−1. The full width half maximum (3 × 10−3 cm−1) of the lines in the experimental spectrum is close to the Doppler–Fizeau width (2.7 × 10−3 cm−1) and the accuracy of the line frequency is better than 10−4 cm−1. The reduced effective Hamiltonian is formulated in terms of irreducible tensorial operators set in the Td group. With 1147 isolated infrared lines, we have determined 10 Hamiltonian parameters for the ground state up to sixth order and 30 parameters of the 0100 and 0001 vibrational states up to the fifth order of approximation. The standard deviation obtained is 10−4 cm−1.

Le niveau de base du silane obtenu à partir de l'étude du spectre à transformée de Fourier de ν2 et ν4

1984 ◽  
Vol 62 (3) ◽  
pp. 254-259 ◽  
Author(s):  
G. Pierre ◽  
A. Valentin ◽  
L. Henry
Keyword(s):  
Fourier Transform ◽  
Standard Deviation ◽  
Ground State ◽  
Excited Level ◽  
Experimental Spectrum ◽  
Fourier Transform Spectrometer ◽  
Apparatus Function ◽  
Vibration Rotation ◽  
The Fourier Transform ◽  
Rotation Spectrum

We have recorded a vibration–rotation spectrum of 28SiH4 from 840 to 1040 cm−1 with a Fourier transform spectrometer operating with an apparatus-function width of 2 × 10−3 cm−1. An analysis of microwave transitions and 919 combination differences between two different ground state levels and an excited level belonging to the band ν2 or ν4 have been used to determine the value of the ground state constants as expressed in a sixth-order Hamiltonian development. The experimental spectrum needed was recorded with the Fourier transform spectrometer of the Laboratoire de Spectronomie Moléculaire de Paris. The experimental precision is about 0.0001 cm−1. The calculation reproduces these 919 differences with a standard deviation of 0.00019 cm−1.

scholarly journals Variety Identification of Orchids Using Fourier Transform Infrared Spectroscopy Combined with Stacked Sparse Auto-Encoder

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2506 ◽  
Author(s):  
Yunfeng Chen ◽  
Yue Chen ◽  
Xuping Feng ◽  
Xufeng Yang ◽  
Jinnuo Zhang ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Principal Component ◽  
Fourier Transform Infrared ◽  
Spectroscopic Technique ◽  
Variety Identification ◽  
Support Vector ◽  
K Nearest Neighbors ◽  
Discriminant Models ◽  
The Fourier Transform ◽  
Better Than

The feasibility of using the fourier transform infrared (FTIR) spectroscopic technique with a stacked sparse auto-encoder (SSAE) to identify orchid varieties was studied. Spectral data of 13 orchids varieties covering the spectral range of 4000–550 cm−1 were acquired to establish discriminant models and to select optimal spectral variables. K nearest neighbors (KNN), support vector machine (SVM), and SSAE models were built using full spectra. The SSAE model performed better than the KNN and SVM models and obtained a classification accuracy 99.4% in the calibration set and 97.9% in the prediction set. Then, three algorithms, principal component analysis loading (PCA-loading), competitive adaptive reweighted sampling (CARS), and stacked sparse auto-encoder guided backward (SSAE-GB), were used to select 39, 300, and 38 optimal wavenumbers, respectively. The KNN and SVM models were built based on optimal wavenumbers. Most of the optimal wavenumbers-based models performed slightly better than the all wavenumbers-based models. The performance of the SSAE-GB was better than the other two from the perspective of the accuracy of the discriminant models and the number of optimal wavenumbers. The results of this study showed that the FTIR spectroscopic technique combined with the SSAE algorithm could be adopted in the identification of the orchid varieties.

Balloon-borne GLORIA hyperspectral Limb and Nadir imager in the LWIR

2021 ◽  
Author(s):  
Erik Kretschmer ◽  
Felix Friedl-Vallon ◽  
Thomas Gulde ◽  
Michael Höpfner ◽  
Sören Johansson ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Optical System ◽  
Late Summer ◽  
High Spectral Resolution ◽  
Fourier Transform Spectrometer ◽  
System Improvement ◽  
The Fourier Transform ◽  
Temperature Retrieval ◽  
Long Wave Infrared ◽  
Better Than

<p>The GLORIA-B (Gimballed Limb Observer for Radiance Imaging of the Atmosphere - Balloon) instrument is an adaptation of the very successful GLORIA-AB imaging Fourier transform spectrometer (iFTS) flown on the research aircrafts HALO and M55 Geophysica. The high spectral resolution in the LWIR (Long Wave Infrared) allows for the retrieval of temperature and of a broad range of atmospheric trace gases, with the goal to retrieve O<sub>3</sub>, H<sub>2</sub>O, HNO<sub>3</sub>, C<sub>2</sub>H<sub>6</sub>, C<sub>2</sub>H<sub>2</sub>, HCOOH, CCl<sub>4</sub>, PAN, ClONO<sub>2</sub>, CFC-11, CFC-12, SF<sub>6</sub>, OCS, NH<sub>3</sub>, HCN, BrONO<sub>2</sub>, HO<sub>2</sub>NO<sub>2</sub>, N<sub>2</sub>O<sub>5</sub> and NO<sub>2</sub>. The radiometric sensitivity of the Balloon instrument is further increased in comparison with the GLORIA-AB instrument by having two detector channels on the same focal plane array, while keeping the same concept of a cooled optical system. This system improvement was achieved with minimal adaptation of the existing optical system.</p><p>The high spatial and temporal resolution of the instrument is ensured by the imaging capability of the Fourier transform spectrometer while stabilizing the line-of-sight in elevation with the instrument and in azimuth with the balloon gondola. In a single measurement lasting 13 seconds, the atmosphere can be sounded from mid-troposphere up to flight altitude, typically 30 km, with a vertical resolution always better than 1 km for most retrieved species; a spatial resolution up to 0.3 km can be achieved in favourable conditions. Temperature retrieval precision between 0.1 and 0.2 K is expected. A spectral sampling up to 0.0625 cm<sup>-1</sup> can be achieved.</p><p>The first flight of GLORIA-B shall take place during the late-summer polar jet turn-around at Kiruna/ESRANGE. This flight is organised in the frame of the HEMERA project and was scheduled for summer 2020, but was ultimately postponed to summer 2021. Beyond qualification of the first balloon-borne iFTS, the scientific goals of the flight are, among others, the quantification of the stratospheric bromine budget and its diurnal evolution by measuring vertical profiles of BrONO<sub>2 </sub>in combination with BrO observations by the DOAS instrument of University Heidelberg on the same platform.</p>

On a Universal Potential Energy Function and the Importance of Ionic Structures for the Ground State of Molecules

1982 ◽  
Vol 37 (9) ◽  
pp. 971-981 ◽  
Author(s):  
G. Van Hooydonk
Keyword(s):  
Potential Energy ◽  
Ground State ◽  
Energy Function ◽  
Potential Energy Function ◽  
Covalent Bonding ◽  
Dissociation Energies ◽  
Reasonable Approximation ◽  
Ionic Dissociation ◽  
Vibrational Levels ◽  
Better Than

Abstract The Kratzer-Fues-Varshni-V-potential, applied to ionic dissociation energies, is shown to yield rather accurate potential energy curves in the bonding region for H2, HF, LiH, Li2 and LiF. Vibrational levels, calculated by this ionic approximation to the ground state of widely differing molecules, nearly coincide with RKR-data. At the repulsive side of the curve and up to 2re, the agreement with RKR-curves is even better than for Morse's curve, also for the "covalent" molecules H2 and Li2. Calculated spectroscopical constants αe and ωeχe are far better than those calculated with Morse's function. Even the existence of a maximum in the potential curve at larger r-values seems not in confict with an ionic approximation. From the universal character of the function used, it is concluded that a reasonable approximation for the ground state of all molecules considered is one in terms of ionic structures, even for H2 and especially for Li2. According to the present results, the term “covalent bonding” seems to be definitely superfluous, as the usually made distinction between ionic and covalent bonding is more appearant than real.

Synthesis and electron spin resonance studies of a Co(II) complex with a tetradentate macrocyclic Schiff base ligand

1977 ◽  
Vol 55 (1) ◽  
pp. 70-75 ◽  
Author(s):  
Amikam Reuveni ◽  
Vincenzo Malatesta ◽  
Bruce R. McGarvey
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Ground State ◽  
Molar Ratio ◽  
Lewis Bases ◽  
Spin Resonance ◽  
Frozen Solutions ◽  
Hamiltonian Parameters ◽  
Simulation Of Spectra ◽  
Macrocyclic Schiff Base

The synthesis, physical properties, and electron spin resonance of frozen solutions of CoTAAB(NO3)2 (TAAB = tetrabenzo[b,f,j,n] [1,5,9,13]tetraazacyclohexadecine) are reported. The spin Hamiltonian parameters were elucidated by simulation of spectra assuming axial g and 59Co hyperfine tensors and including nuclear quadrupole and Zeeman contributions. Electron spin resonance spectra in solvents such as methanol, acetone, and dimethylformamide are typical for a low spin complex (S = 1/2) and are nearly identical with [Formula: see text] and [Formula: see text]. In pyridine and quinoline a complex with a molar ratio solvent/ligand of 1:1 is formed with the solvent which gives [Formula: see text]and [Formula: see text] much closer to [Formula: see text]. In strong Lewis bases, such as piperidine, a 2:1 complex is formed and no esr signal is found. Evidence is presented to show that these 2:1 complexes with strong Lewis bases are S = 1/2 complexes with a low lying S = 3/2 state that is partially populated at room temperatures. This behaviour is accounted for in terms of a theory derived for a 2A1 ground state with a low lying quartet state which could become the ground state in strong basic solvents.

Millimeter wave study of the ground state and several excited vibrational states of trioxane

1970 ◽  
Vol 34 (2) ◽  
pp. 190-205 ◽  
Author(s):  
Jean Bellet ◽  
Jean-Marcel Colmont ◽  
Jean Lemaire
Keyword(s):  
Millimeter Wave ◽  
Ground State ◽  
Vibrational States

scholarly journals Quantum computation solves a half-century-old enigma: Elusive vibrational states of magnesium dimer found

2020 ◽  
Vol 6 (14) ◽  
pp. eaay4058 ◽  
Author(s):  
Stephen H. Yuwono ◽  
Ilias Magoulas ◽  
Piotr Piecuch
Keyword(s):  
Ground State ◽  
State Of The Art ◽  
Coupled Cluster ◽  
Experimental Investigations ◽  
Experimental Characterization ◽  
Vibrational States ◽  
Vibrational Levels ◽  
State Potential ◽  
Derived Data ◽  
Important System

The high-lying vibrational states of the magnesium dimer (Mg2), which has been recognized as an important system in studies of ultracold and collisional phenomena, have eluded experimental characterization for half a century. Until now, only the first 14 vibrational states of Mg2 have been experimentally resolved, although it has been suggested that the ground-state potential may support five additional levels. Here, we present highly accurate ab initio potential energy curves based on state-of-the-art coupled-cluster and full configuration interaction computations for the ground and excited electronic states involved in the experimental investigations of Mg2. Our ground-state potential unambiguously confirms the existence of 19 vibrational levels, with ~1 cm−1 root mean square deviation between the calculated rovibrational term values and the available experimental and experimentally derived data. Our computations reproduce the latest laser-induced fluorescence spectrum and provide guidance for the experimental detection of the previously unresolved vibrational levels.

scholarly journals Complex formation in a liquid-liquid extraction-chromogenic system for vanadium(IV)

2019 ◽  
Vol 17 (1) ◽  
pp. 599-608 ◽  
Author(s):  
Kiril B. Gavazov ◽  
Vassil B. Delchev ◽  
Nikolina P. Milcheva ◽  
Galya K. Toncheva
Keyword(s):  
Complex Formation ◽  
Ground State ◽  
Experimental Spectrum ◽  
Molar Absorptivity ◽  
Equilibrium Geometry ◽  
Ortho Position ◽  
Unusual Structure ◽  
Tetrazolium Chloride ◽  
State Equilibrium ◽  
Equilibrium Geometries

AbstractThe azo dye 4-(2-thiazolylazo)orcinol (TAO) and the cationic ion-pair reagent 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) were examined as constituents of a water-chloroform extraction-chromogenic system for vanadium(IV). The effects of TAO concentration, TTC concentration, pH and extraction time were examined. Under the optimum conditions the extracted complex has a composition of 1:2:1 (V:TAO:TTC). The absorption maximum, molar absorptivity and constant of extraction were determined to be λmax=544 nm, ε544=1.75×104 dm3 mol–1 cm–1 and Log Kex=4.1. The ground state equilibrium geometries of the possible monoanionic VIV-TAO 1:2 species were optimized by the HF method using 3-21G* basis functions. Their theoretical time dependent electronic spectra were simulated and compared with the experimental spectrum. The best fit was obtained for the structure in which one of the TAO ligands is tridentate, but the other is monodentate (bound to VIV through the oxygen which is in the ortho-position to the azo group) and forms a hydrogen bond N–H...O=V through its protonated heterocyclic nitrogen. Based on this unusual structure, which can explain some peculiarities of the complex formation between VIV and commonly used azo dyes, the ground state equilibrium geometry of the whole ternary 1:2:1 complex was computed at the HF and BLYP levels.

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