Analysis Of Ν1 Research Articles

Observation and analysis of ν1 + ν3 and ν1 + 2ν4 bands of CF4 molecule

Infrared spectra of CF4 molecule were measured for three different temperatures in the range 2160–2210 cm−1 using Fourier transform spectrometer. Non-empirical effective Hamiltonian obtained from the potential energy surface using the contact transformation method was used for the modeling of line positions. The origins of two bands ν1 + ν3 (F2) and ν1 + 2ν4 (F2) at 2186.97 and 2168.21 cm−1 were experimentally determined for the first time. The experimental origin of the weak ν1 + 2ν4 (E) sub-band was tentatively evaluated near 2169.84 cm−1. Ab initio line intensities were calculated from high order dipole moment surface by variational method using the TENSOR computational code in the normal mode representation. The analyses of experimental spectra were carried out using the MIRS program suite accounting for the full tetrahedral symmetry of the molecule.

Studies of low-frequency intermolecular hydrogen-bonded vibrations using a continuous supersonic slit jet mid-infrared quantum cascade laser spectrometer

Rovibrational manifolds in low frequency intermolecular vibrations of prototypical hydrogen-bonded interactions OC–HX (X=F, Cl, CN) are reported using a near infrared quantum cascade cw supersonic jet spectrometer. (i) OC–HCl is studied to evaluate future capabilities of the QCL spectrometer. (ii) Analysis of OC–HF demonstrates applicability to vibrations greater than 80cm−1 above the ground state. ν51 band origins in OC–1H35Cl and OC–1H19F are 48.9944(2) and 81.96825(12)cm−1 respectively. (iii) The corresponding intermolecular ν71 band origin of OC–HCN is 34.63742(18)cm−1 and its corresponding rovibrational spectrum made available for attempted detection in interstellar space. Analysis of ν2, ν2+ν71-ν71, ν2+ν71, and ν2+ν61 vibrations in OC–HCN also enables generation of its 5-dimensional semi-empirical intermolecular potential. Structural and other properties of OC–HCN are then compared with corresponding properties predicted using morphed potentials for the homologous series OC–HX (X=F, Cl, Br, I). These results permit investigation of blue shifts in OC vibrations for this homologous series.

ChemInform Abstract: Diode Laser Measurements of CF3Cl Near 1258 cm-1: Rovibrational Analysis of ν2 + ν3 Combination and Its Hot Bands.

Abstract The gas-phase infrared spectrum of natural CF 3 Cl has been investigated in the range 1244–1275 cm −1 with a resolution of about 0.002 cm −1 using a tunable diode laser spectrometer. The K structure of many P ( J ) and R ( J ) clusters of the ν 2 + ν 3 band has been resolved and analyzed: the maximum J values reached for individual transitions were 66 and 62 for CF 3 35 Cl and CF 3 37 Cl, respectively. Small irregularities found in the K = 15, 18 lines of most manifolds of the main species have been attributed to perturbations with the ν 5 + 2 ν 6 vibration, and different interaction mechanisms have been considered. From a least-squares fit of the assigned transitions, accurate parameters up to the quartic terms have been determined for the ν 2 + ν 3 combination of both the isotopomers. Residual features due to the hot bands ν 2 + 2 ν 3 − ν 3 and ν 2 + ν 3 + ν 6 − ν 6 of CF 3 35 Cl have also been identified and spectroscopic constants have been derived by polynomial and manifold contour simulation methods.

Trans–cis isomerisation of the carotenoid lycopene upon complexation with cholesteric polyester carriers investigated by Raman spectroscopy and density functional theory

AbstractRaman spectroscopy and density functional theory (DFT) were used in this work for the structural characterisation of lycopene, the antioxidant carotenoid, and its complexes with two synthetic thermotropic cholesteric polyesters. Both polyesters were employed successfully to encapsulate the carotenoid lycopene (Lyc). Besides protecting it from oxidation, they induced the trans–cis isomerisation of lycopene towards the more biologically active and bioavailable isomer cis‐Lyc. The Raman spectra revealed changes mainly concerning the band ν1 and bands of methyl groups. This would explain the interaction mechanism between lycopene and cholesteric polyesters, inducing structural changes in the carotenoid by formation of a cis CC bond in central positions of the isomer chain and hydrophobic interaction that affects the side methyl groups. DFT calculations confirmed that the isomerisation occurs at central positions of lycopene molecule. The analysis of ν1 and ν2 bands and those of methyl groups in the calculated spectra of lycopene indicates that the interaction with the synthetic cholesteric polyesters could mainly lead to the 13‐cis‐Lyc isomer. The analysis of marker structural bands of the polyesters revealed structural changes in the host which mainly affect the ester groups, most probably due to a restructuring of the polyester chain to better accommodate the ligand. Copyright © 2010 John Wiley & Sons, Ltd.

Infrared Spectrum of Ozone in the 4600 and 5300 cm−1Regions: High Order Accidental Resonances through the Analysis of ν1+ 2ν2+ 3ν3− ν2, ν1+ 2ν2+ 3ν3, and 4ν1+ ν3Bands

The very weak bands ν1+ 2ν2+ 3ν3and 4ν1+ ν3of16O3have been observed for the first time, using the Fourier transform spectrometer (FTS) of Reims and the usual experimental setup providing a large productp × lof approximately 38 Torr × 36 m. The upper levels of these A-type bands which are rather close in energy (they appear respectively at 5291.722 and 5307.790 cm−1) belong to two different sets of interacting polyads. To correctly reproduce the rotation–vibration energy levels and account for the observed perturbations, both bands are treated in a dyad approximation: the (123) state in the Coriolis resonance with the (330) state, and the (401) state in the Coriolis resonance with the (024) state. The assignments of the rotation–vibration levels of the (123) state are confirmed by measurements of line positions of the hot band ν1+ 2ν2+ 3ν3− ν2which has also been observed for the first time. The fits are very satisfactory: the r.m.s. deviation for 249 energy levels of the (123) state is 2.4 × 10−3cm−1and is 2.0 × 10−3cm−1for 266 levels of the (401) state. These r.m.s. are near experimental accuracy. Transition moments for the three observed bands are determined from measured line intensities.

High resolution, jet-cooled infrared spectroscopy of (HCl)2: Analysis of ν1 and ν2 HCl stretching fundamentals, interconversion tunneling, and mode-specific predissociation lifetimes

An extensive series of near-infrared absorption spectra are recorded for jet-cooled (6–14 K) hydrogen chloride dimer (HCl)2. Both ΔKa=0 and ΔKa=±1 bands are observed for both the free (ν1) and bonded (ν2) HCl stretches; all three chlorine isotopomers (H 35Cl–H 35Cl, H 35Cl–H 37Cl, and H 37Cl–H 37Cl) are observed and analyzed for K″a ≤ 2. The slit jet spectrum extends significantly the previous cooled cell infrared study of this complex and provides a measure of tunneling splittings for Ka=0 and 1 for each of the HCl ground (v=0) and excited (v=1) states. Mode specific vibrational predissociation is observed via analysis of the absorption line shapes, with Lorentzian contributions to the line profiles of Δν1≲1.6 MHz and Δν2=5.1±1.2 (2σ) MHz full width at half-maximum for ν1 and ν2 excitation, respectively. Stronger coupling in (HCl)2 of the bonded (ν2) vs free (ν1) HCl vibration to the dissociation coordinate is consistent with the comparable trends observed in other hydrogen bonded dimers. Quantum mechanical variational calculations on an electrostatic angular potential energy surface are used to model the internal HCl rotor dynamics using a coupled rotor formalism; analysis of the internal rotor eigenfunctions provides direct evidence for large amplitude ‘‘geared’’ internal rotation of the HCl subunits.

High resolution IR laser spectroscopy of van der Waals complexes in slit supersonic jets: Observation and analysis of ν1, ν1+ν2, and ν1+2ν3 in ArHF

IR spectra of jet cooled ArHF are obtained via direct absorption of a high resolution tunable difference frequency laser in a 2.54 cm path length, slit supersonic pulsed expansion at <10 K. Detection limits of 2×109 molecules/cm3/quantum state permit observation of the high frequency ν1 fundamental stretch (1000) ← (0000), the ν1+ν2 van der Waals bend plus stretch combination band (1110) ← (0000), as well as transitions to the (1002) triply vibrationally excited state that are weakly allowed via Coriolis interactions with the Π+ component of the (1110) manifold. The ground state (0000) molecular constants are in excellent agreement with previous microwave data. From the changes in rotational and centrifugal distortion constants, the vibrationally averaged van der Waals well depth is estimated to increase (+15%) with ν1 excitation, but decrease dramatically (−42%) upon subsequent excitation of the l=1 ν2 bend. L-doubling in the ν1+ν2 (1110) perpendicular bending state is large and negative [−69.8(18) MHz] and indicates the presence of a near resonant Coriolis coupled vibration of Σ+ symmetry at lower energy. A second, localized Coriolis perturbation is observed in the (1110) state and assigned to the near resonant (1002) Σ+ fundamental plus van der Waals stretch overtone at higher energy. Analysis of this Coriolis interaction indicates that coupling can be significant even for a three quantum change in vibration. However, a perturbative, small amplitude oscillator model predicts Coriolis matrix elements only 18% of the observed values, suggesting that large amplitude, bend–stretch interactions can strongly enhance Coriolis coupling. The decrease in the B rotational constant and the vibrationally averaged well depth upon ν2 excitation confirms the strong coupling between van der Waals stretch and bend coordinates. The slit expansion geometry quenches perpendicular velocity distributions and therefore offers intrinsically sub-Doppler resolution in an unskimmed molecular beam. Residual linewidths in the ArHF spectra are all below the apparatus resolution limit of ±25 MHz, which translates into a lower limit for the predissociation lifetime of 3 ns, i.e., in excess of 2×106 ν1 vibrational periods.

ChemInform Abstract: HIGH‐RESOLUTION INFRARED ATMOSPHERIC SPECTRA OF OZONE IN THE 10 μM REGION: ANALYSIS OF ν1 AND ν3 BANDS ‐ ASSIGNMENT OF THE (ν1 + ν2) ‐ ν2 BAND

Chemischer InformationsdienstVolume 12, Issue 33 Physical Inorganic Chemistry ChemInform Abstract: HIGH-RESOLUTION INFRARED ATMOSPHERIC SPECTRA OF OZONE IN THE 10 μM REGION: ANALYSIS OF ν1 AND ν3 BANDS - ASSIGNMENT OF THE (ν1 + ν2) - ν2 BAND A. BARBE, A. BARBESearch for more papers by this authorC. SECROUN, C. SECROUNSearch for more papers by this authorP. JOUVE, P. JOUVESearch for more papers by this authorA. GOLDMAN, A. GOLDMANSearch for more papers by this authorD. G. MURCRAY, D. G. MURCRAYSearch for more papers by this author A. BARBE, A. BARBESearch for more papers by this authorC. SECROUN, C. SECROUNSearch for more papers by this authorP. JOUVE, P. JOUVESearch for more papers by this authorA. GOLDMAN, A. GOLDMANSearch for more papers by this authorD. G. MURCRAY, D. G. MURCRAYSearch for more papers by this author First published: August 18, 1981 https://doi.org/10.1002/chin.198133003AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume12, Issue33August 18, 1981 RelatedInformation

High-resolution infrared atmospheric spectra of ozone in the 10-μm region: Analysis of ν1 and ν3 bands-assignment of the ( ν1 + ν2) − ν2 band

1988 lines of ozone have been observed in the atmospheric spectrum in the region 1060 to 1220 cm −1, 1394 of them have been assigned to the ν 1 band, and 480 to the ν 3, particularly corresponding to Δ K −1 = 2. The analysis has been performed using the Watson Hamiltonian, taking account of the strong Coriolis coupling between the 001 and 100 levels. The constants for the latter two states, the spectra and a listing of the observed and calculated wave-numbers, with their assignment, are given. In addition, 114 lines of the “hot” band ( ν 1 + ν 2) − ν 2 have been observed and assigned and are reported.

Spectrum of phosphine at 4 to 5 μm: Analysis of ν1 and ν3 bands

The absorption spectrum of phosphine has been investigated in the region 2087–2482 cm −1. About 1200 transitions belonging to the bands ν 1 and ν 3 were assigned. A strong Coriolis interaction between these bands gives rise to many “forbidden” transitions and large A 1 A 2 splittings. The simultaneous analysis of the two bands enabled us to get a set of vibration-rotation constants for the vibrational states v 1 = 1 and v 3 = 1, and to obtain a value for the ratio S 1 S 3 between the band strengths of ν 1 and ν 3.

Vibrational spectra and force constants of symmetric tops: Rotational analysis of ν1, ν1 + ν6 − ν6, and ν1 + 2ν6 − 2ν6 of CF379Br and CF381Br near 1100 cm−1

Abstract The gas phase infrared spectrum of CF 3 Br has been recorded in the ν 1 range between 1070 and 1100 cm −1 with a resolution of 0.015 cm −1 . The spectrum comprises mainly the fundamental ν 1 and the two “hot” bands ν 1 + ν 6 − ν 6 and ν 1 + 2 ν 6 − 2 ν 6 of the 79 Br and 81 Br species. The isotopic splitting amounts to 0.242 cm −1 , and x 16 was determined to be −1.237 cm −1 . The P and R branches were resolved into J lines which were assigned to the six different rovibrational band systems. The molecular parameters ν 0 , B 0 , α 1 A , α 1 B , and α 6 B were determined by a least-squares analysis and a band contour simulation procedure.

Simultaneous least squares analysis of ν2 + ν4, ν4 + ν5 and 2 ν4 of CD 3I

The spectrum of CD 3I between 3100 cm −1 and 3400 cm −1 has been measured with a resolution of ∼0.06 cm −1 and three bands assigned to ν 1 + ν 5, ν 2 + ν 4 and ν 4 + ν 5. The fine structure has been assigned unequivocally for ν 2 + ν 4, and ν 4 + ν 5 and least squares analyses performed on the data for these two bands. A simultaneous least squares analysis of ν 2 + ν 4, ν 4 + ν 5 and previously published data for 2 ν 4 has been carried out using the twice transformed Hamiltonian through third order. Advantages of simultaneous analysis of related bands for the isolation of the effects of localized resonances and accurate determination of molecular parameters are discussed.

Boron Trifluoride: The Analysis of ν2 and the Determination of the Molecular Geometry

The parallel band ν2 of 10BF3 has been remeasured with a resolution of about 0.03 cm−1 and new values of the rotational constants have been determined. The values of B0 = 0.34474 ± 0.0005 (10BF3) and B0 = 0.34505 ± 0.0005 cm−1 (11BF3) are consistent with the geometry obtained in the electron-diffraction experiments of Kuchitsu and Konaka, but differ appreciably from the values previously reported by Nielsen. From our results we obtain r0 = 1.3096 ± 0.001 Å (10BF3), re = 1.3090 ± 0.001 Å (11BF3), and r0 = 1.3072 ± 0.002 Å (10BF3). From the analysis of the hot bands we have determined values of (B′ − B″) for ν4 and some of the anharmonic constants xss′.

The Infrared Spectrum of Chlorine Dioxide

The infrared spectrum of ClO2has been reinvestigated from 2–40μ. Several new bands have been discovered, among them the bending frequency ν2 at 445 cm−1. This band has the doublet character required if the molecular model is to be an obtuse triangle in accord with electron diffraction experiments. Three bands, ν1, ν2, and 2ν1, were resolved with prism and grating methods, and the spacing of the Q lines was found to be about 3.0 cm−1. An A″—B″ value of 1.413 cm−1 was obtained from the analysis of ν2, and this value also is in excellent agreement with the electron diffraction measurements. Moments of inertia computed from the r(Cl–O) = 1.49A and 2α (apex angle) = 118.5° obtained from a combination of electron diffraction and infrared data are IA=16.09×10−40 g cm2, IB=86.35×10−40 g cm2, and IC=102.43×10−40 g cm2. A band which cannot be ascribed to an impurity was found at 290 cm−1. The possibility that this band results from polymerization of ClO2 is suggested.