scholarly journals Криоспектроскопическое исследование резонансных мультиплетов ν-=SUB=-s-=/SUB=- ~2ν-=SUB=-b-=/SUB=- в молекуле CHF-=SUB=-3-=/SUB=-

2021 ◽  
Vol 129 (8) ◽  
pp. 1019
Author(s):  
С.М. Меликова ◽  
К.С. Рутковский ◽  
Д.Н. Щепкин ◽  
С. Махолл ◽  
В. Херребут
Keyword(s):  
Ir Spectrum ◽  
Vibrational Excitation ◽  
Interaction Constant ◽  
Correct Description ◽  
Bending Vibration ◽  
Quantum Numbers ◽  
Stretching Vibration ◽  
High Degree ◽  
Anharmonic Interaction ◽  
Fermi Resonances

The sequences of Fermi resonances vs~2vb in the IR spectrum of a solution of fluoroform (CHF3) in liquefied krypton are investigated. Here vs is the CH stretching vibration, vb is the bending vibration. It is shown that for a correct description of resonance multiplets (polyads) at a high degree of vibrational excitation, it is necessary to use an extended set of spectroscopic parameters. In particular, it is necessary to take into account the dependence of the anharmonic interaction constant asbb on the vibrational quantum numbers. The conclusions are generalized for the arbitrary case of the CH-chromophore CHX3.

scholarly journals Comparing the Efficiencies of the Removal of Cadmium from Industrial Wastewater Using Zeolites

2020 ◽  
pp. 6-18
Author(s):  
Michael Akrofi Anang ◽  
Ruphino Zugle ◽  
Baah Sefa- Ntiri
Keyword(s):  
Rice Husk ◽  
Industrial Wastewater ◽  
Raw Materials ◽  
Research Work ◽  
Corn Stalk ◽  
Zeolite X ◽  
Bending Vibration ◽  
Strong Peak ◽  
Corn Husk ◽  
Stretching Vibration

The presence of heavy metals in industrial wastewater needed to be removed in other to control pollution which has been caused as a result of human and industrial activities. Several adsorbents have been used for the remediation process but with this particular research work, Zeolites were used. They were synthesized hydrothermally from various locally available raw materials namely rice husk, corn stalk, corn husk, and kaolin. They were characterized using their FTIR to determine the functional groups on the material synthesized and also their adsorptive activities were compared with industrially synthesized Zeolite X. A very strong peak at 1052 cm-1 is as a result of the asymmetric vibrations of the internal T-O tetrahedron with a weak symmetric T-O stretching vibration recorded at 797 cm-1. Another strong peak was observed at 445 cm-1 as a result of the O-T-O bending vibration which confirms the presence of a five-membered structure. The adsorptive properties of the synthesized Zeolites were evaluated by using them to remove Cadmium ions from solution and their percentage removals were determined. Similarly, their adsorption kinetics were also determined and was observed the R2 values to be 0.9093 and 0.9454 for Corn husk and Cornstalk for the first order and the second order with R2 values of 1 for rice husk, kaolin and corn stalk.

scholarly journals Micro-FTIR and EPMA Characterisation of Charoite from Murun Massif (Russia)

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Maria Lacalamita
Keyword(s):  
Single Crystal ◽  
Complex Structure ◽  
Structural Complexity ◽  
Adsorbed Water ◽  
Bending Vibration ◽  
Structural Water ◽  
Stretching Vibration ◽  
Vibrational Features ◽  
Polytype Structure ◽  
Insight Into

Combined micro-Fourier transform infrared (micro-FTIR) and electron probe microanalyses (EPMA) were performed on a single crystal of charoite from Murun Massif (Russia) in order to get a deeper insight into the vibrational features of crystals with complex structure and chemistry. The micro-FTIR study of a single crystal of charoite was collected in the 6000–400 cm−1 at room temperature and after heating at 100°C. The structural complexity of this mineral is reflected by its infrared spectrum. The analysis revealed a prominent absorption in the OH stretching region as a consequence of band overlapping due to a combination of H2O and OH stretching vibrations. Several overtones of the O-H and Si-O stretching vibration bands were observed at about 4440 and 4080 cm−1 such as absorption possibly due to the organic matter at about 3000–2800 cm−1. No significant change due to the loss of adsorbed water was observed in the spectrum obtained after heating. The occurrence of well-resolved water bending vibration bands at about 1595 and 1667 cm−1 accounts for more than one structural water molecule as expected by charoite-90 polytype structure model from literature. The chemical composition of the studied crystal is close to the literature one.

FTIR STUDY ON MOLECULAR CONTAMINATION ON SURFACE OF OPTICAL MATERIALS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3860-3865 ◽  
Author(s):  
MASAHIRO KATOH ◽  
NOBUAKI OKANO ◽  
TOSHIHIDE HORIKAWA ◽  
TAHEI TOMIDA ◽  
NOBUNARI ITOH
Keyword(s):  
Ir Spectra ◽  
Optical Materials ◽  
Functional Group ◽  
The Other ◽  
Absorption Bands ◽  
Bending Vibration ◽  
Absorption Intensity ◽  
Stretching Vibration ◽  
Optical Disks ◽  
Molecular Contaminants

The IR spectra of the molecular contaminants on surface of optical materials were measured. The optical disks used were SiO 2, BK7 ( SiO 2 70%, B 2 O 3 10%, K 2 O 8%, N 2 O 8%), CaF 2, ZnSe and Al 2 O 3. N 2, O 2, H 2 O , and CO 2 were adopted as contamination gases. IR spectra of H 2 O (2.7kPa) on BK7 at 373K showed two absorption bands ( OH stretching vibration: around 4000cm-1-3500cm-1 and OH bending vibration: around 2000cm-1-1500cm-1). The absorption intensity decreased with a decrease in temperature and a new band (around 3250cm-1) appeared at 173K. The new band was attributed to phase transition of H 2 O . These phenomena were also observed on the other three discs, except for SiO 2. IR spectra of SiO 2 showed OH stretching band (3676cm-1). The absorption intensity decreased with a decrease in temperature. But two new bands (3720cm-1 and 3620cm-1) appeared under an atmosphere of N 2 (66.5kPa), O 2 (66.5kPa), H 2 O (2.7kPa) or CO 2 (0.7 or 13.3kPa). A similar phenomenon was also observed for BK7, which has OH group. These results suggested the functional group of SiOH interacted with contamination molecules.

scholarly journals EXOCROSS: a general program for generating spectra from molecular line lists

2018 ◽  
Vol 614 ◽  
pp. A131 ◽  
Author(s):  
Sergei N. Yurchenko ◽  
Ahmed F. Al-Refaie ◽  
Jonathan Tennyson
Keyword(s):  
Partition Function ◽  
Line Profiles ◽  
Molecular Line ◽  
Specific Heats ◽  
Quantum Numbers ◽  
Fortran Code ◽  
General Program ◽  
Vibrational Bands ◽  
High Degree ◽  
Two Temperature

EXOCROSS is a Fortran code for generating spectra (emission, absorption) and thermodynamic properties (partition function, specific heat, etc.) from molecular line lists. Input is taken in several formats, including ExoMol and HITRAN formats. EXOCROSS is efficiently parallelized showing also a high degree of vectorization. It can work with several line profiles such as Doppler, Lorentzian and Voigt and support several broadening schemes. Voigt profiles are handled by several methods allowing fast and accurate simulations. Two of these methods are new. EXOCROSS is also capable of working with the recently proposed method of super-lines. It supports calculations of lifetimes, cooling functions, specific heats and other properties. EXOCROSS can be used to convert between different formats, such as HITRAN, ExoMol and Phoenix. It is capable of simulating non-LTE spectra using a simple two-temperature approach. Different electronic, vibronic or vibrational bands can be simulated separately using an efficient filtering scheme based on the quantum numbers.

Dimethyl Phthalate, a Neutral Bidentate Oxygen-Donor Ligand to Divalent Metal Ions

1977 ◽  
Vol 32 (11) ◽  
pp. 1284-1286 ◽  
Author(s):  
W. L. Driessen ◽  
P. L. A. Everstijn
Keyword(s):  
Metal Ions ◽  
Divalent Metal ◽  
Dimethyl Phthalate ◽  
Divalent Metal Ions ◽  
Melting Points ◽  
Bending Vibration ◽  
Donor Ligand ◽  
Oxygen Donor ◽  
Stretching Vibration ◽  
Metal Ligand

A series of new coordination compounds is reported with dimethyl phthalate (MPH) as the ligand, viz. [M(MPH)3](InCl4)2 with M=Mg(II), Ca(II), Mn(II), Fe(II), Co(II), Ni(II), and Zn(II). Each of the metal ions is bonded to three dimethyl phthalate molecules, the six carbonyl oxygens forming a regular octahedron. The carbonyl stretching vibration shifts to lower frequencies, the carbonyl bending vibration shifts to higher frequencies. The magnitudes of the shifts of these vibrations, the frequencies of the metal-ligand vibrations, and the melting points follow the Irving-Williams sequence.

scholarly journals Surface-enhanced infrared absorption studies towards a new optical biosensor

2016 ◽  
Vol 7 ◽  
pp. 1736-1742 ◽  
Author(s):  
Lothar Leidner ◽  
Julia Stäb ◽  
Jennifer T Adam ◽  
Günter Gauglitz
Keyword(s):  
Infrared Absorption ◽  
Resonance Effect ◽  
Optical Biosensor ◽  
Fermi Resonance ◽  
Infrared Range ◽  
Bending Vibration ◽  
Thickness Change ◽  
Additional Information ◽  
Surface Enhanced ◽  
Stretching Vibration

Reflectometric interference spectroscopy (RIfS), which is well-established in the visual regime, measures the optical thickness change of a sensitive layer caused, e.g., by binding an analyte. When operated in the mid-infrared range the sensor provides additional information via weak absorption spectra (fingerprints). The originally poor spectra are magnified by surface-enhanced infrared absorption (SEIRA). This is demonstrated using the broad complex fluid water band at 3300 cm−1, which is caused by superposition of symmetric, antisymmetric stretching vibration, and the first overtone of the bending vibration under the influence of H-bonds and Fermi resonance effect. The results are compared with a similar experiment performed with an ATR (attenuated total reflectance) set-up.

Analysis of the Structures and Thermal Properties of Hexanediamine Adipate and Pentanediamine Adipate

2018 ◽  
Vol 876 ◽  
pp. 76-83
Author(s):  
Xiao Wan Yang ◽  
Xin Min Hao ◽  
Jian Ming Wang ◽  
Yan Bin Liu ◽  
Hong Liang Kang
Keyword(s):  
Thermal Properties ◽  
Melting Point ◽  
Infrared Spectra ◽  
Adipic Acid ◽  
Decomposition Temperature ◽  
Bending Vibration ◽  
Out Of Plane ◽  
Stretching Vibration ◽  
Acid Reaction ◽  
The Difference

Hexanediamine adipate, pentanediamine adipate and bio-based pentanediamine adipate were prepared by adipic acid reaction with 1,6-hexanediamine, 1,5-pentanediamine and bio-based 1,5-pentanediamine, respectively. Their structures and thermal properties have been analyzed by infrared spectra, SEM, DSC and TGA. Infrared spectra showed the main differences between 1,6-hexanediamine and 1,5-pentanediamine for the deformation vibration and out of plane bending vibration of N−H. Hexanediamine adipate and pentanediamine adipate had the difference at the asymmetric stretching vibration of −COO-−. The crystal morphologies of hexanediamine adipate and pentanediamine adipate showed dendritic and acicular, respectively. The melting point of pentanediamine adipate, pentanediamine adipate and bio-based pentanediamine adipate were 208.0 °C, 182.3 °C and 182.9 °C, respectively. The polymerization of hexanediamine adipate, pentanediamine adipate and bio-based pentanediamine adipate happened at 201.0, 190.2 and 194.9 °C, respectively. And the decomposition temperature of PA66, PA56 and bio-based PA56 were 401.8, 403.5 and 405.2 °C, respectively.

The electronic absorption spectra of NH 2 and ND 2

1959 ◽  
Vol 251 (1002) ◽  
pp. 553-602 ◽  
Keyword(s):  
Excited State ◽  
Bond Length ◽  
Absorption Spectra ◽  
Flash Photolysis ◽  
Electronic Absorption Spectra ◽  
Interaction Constant ◽  
Bending Vibration ◽  
Vibronic Structure ◽  
Linear Configuration ◽  
Centrifugal Distortion Constants

The absorption spectra of <super>14</super>NH 2 , <super>15</super>NH 2 and <super>14</super>ND 2 have been photographed in the region 3900 to 8300 A with a 21 ft. concave grating spectrograph. The radicals are produced by the flash photolysis of <super>14</super>NH 3 , <super>15</super>NH 3 and <super>14</super>ND 3 respectively. A detailed study of the <super>14</super>NH 2 - <super>15</super>NH 2 isotope shifts suggests that the molecule has a linear configuration in the excited state and that the spectrum consists of a long progression of the bending vibration in this state. These conclusions have been confirmed by detailed rotational and vibrational analyses of the 14NH2 and 14ND2 spectra. The spectra consist of type C bands for which the transition moment is perpendicular to the plane of the molecule. For NH2, sixteen bands of the progression (0, v'%, 0) <- (0, 0, 0) have been identified with v'% — 3, 4, ..., 18. In addition four bands of a subsidiary progression (1, v'2, 0) <- (0, 0, 0) have been found; these bands derive most of their intensity from a Fermi-type resonance between (0, v'2) 0) and (1, v2 —4, 0) levels in the excited state. The interaction constant W nl is 72 + 3 cm <super>-1</super>. For ND 2 , fourteen bands of the principal progression (v2 — 5 to 18) and one band of the subsidiary progression have been identified. The upper state vibration frequencies w?' and (i)' are 3325 cm <super>-1</super> and 622 cm <super>-1</super> for NH 2 and 2520 cm <super>-1</super> and 422 cm <super>-1</super> for ND 2 respectively. The bending frequencies are unusually low ; moreover, the anharmonicities of the bending vibration are unusually large and negative (x22—11.4 cm <super>-1</super> for NH 2 and 8.1 cm <super>-1</super> for ND 2 ). The origin of the system lies in the region o f 10000 cm <super>-1</super>. Ground-state rotational term values have been derived from observed com bination differences; values for the rotational constants Aooo, B'ooo and Cooo and for the centrifugal distortion constants D"A, D"b and D"0 have been determined. The bond lengths and bond angles for NH 2 and ND 2 agree and are 1.024 + 0.005 A and 103° 20' + 30' respectively. Small spin splittings have been observed. In the excited state an unusual type of vibronic structure has been found. Successive levels of the bending vibration consist alternately of 27, d , T, ... and ... vibronic sub-levels with large vibronic splittings. The origins of the vibronic sub-bands may be represented by the formula yf = Vq—GK2, where G is ~ 27 cm -1 for NH 2 and ~ 19 cm <super>-1</super> for ND 2 . The rotational levels show both spin and A-type doubling. No simple formula has been found to fit the energies o f the II, A, 0 and -T rotational levels; the 27 levels fit the formula F(N) = 1) — D N2(N + 1)2, though with a negative value for D . By extrapolating the B values for the 27 levels to = 0 we obtain B'00o = 8.7 8 cm <super>-1</super> for NH 2 and 4.4 1 cm<super>-1</super> for ND 2 . These values are consistent with a linear configuration with a bond length of 0.97 5 A. The significance of this short bond length is discussed. An explanation of the complex vibronic structure is given. The two combining states are both derived from an electronic II state which is split by electronic-vibrational coupling for the reasons advanced by Renner. A detailed correlation diagram is given. A quantitative treatment of this effect by Pople & Longuet-Higgins gives good agreement with the experimental data.

scholarly journals Synthetic Characterization of Cellulose from Moringa oleifera seeds and Potential Application in Water Purification

2021 ◽  
Author(s):  
A. F. Afolabi ◽  
S. S. Oluyamo ◽  
I. A. Fuwape
Keyword(s):  
Water Purification ◽  
Moringa Oleifera ◽  
Crystallinity Index ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Bond Stretching ◽  
Stretching Vibration ◽  
High Degree

The use of Moringa oleifera seeds for purifying water has been attempted locally in various forms without putting scientific potency of the material into consideration. The cellulose sample isolated from Moringa {oleifera} seed was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The value of the crystallinity index (CIr ) from the XRD pattern is 63.1%. The high degree of crystallinity obtained is attributed to the high percentage of crystallinity index, CIr (i.e. 63.1%). The morphology revealed aggregates of conical and needle-like structure. The FTIR revealed O-H stretching, C-H stretching vibration, and C=O bond stretching functional groups. These characteristics are indicative of the potential of the material in water purification.

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.

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