共查询到20条相似文献,搜索用时 15 毫秒
1.
N.D. Sokolov 《Journal of Molecular Liquids》1984,29(4):231-242
It is proposed that broadening of the νs (AH) IR band is due to the νs (AH) and νσ (AH…B) mode coupling and to the stochastic variation of the equilibrium distance Re (A…B) modulating the proton vibration. The Re disordering variation is caused by a coupling of the νσ mode with the low frequency oscillators (νQ) of the medium and of the complex as such. Besides, the (νσ, νQ) and (νs, νσ) couplings cause a νs frequency shift. Both the band broadening and the frequency shift increase with higher force constants responsible for (νσ, νQ) mode coupling. Furthermore the Qi low frequency stochastic vibrations directly modulate the νσ (AH…B) vibration and the free AH groups stretching vibration (νos) causing some broadening at their bands which is however several times smaller than the νs band broadening in the complex. Several examples are reported to confirm the proposed model. 相似文献
2.
采用包含Davidson修正的多参考组态相互作用(MRCI+Q)方法结合6-311++G(3df,3pd)基组计算了LiC分子基态(X4Σ-)以及五个低电子激发态(a2Π,b2Δ,c2Σ-,d2Σ+,A4Π)的势能曲线.将得到的势能曲线拟合到Murrell-Sorbie解析势能函数形式,确定了对应态的平衡结构Re、谐振频率ωe和离解能De等光谱数据,计算值与仅有的几个其他结果进行了比较.通过求解核运动的薛定谔方程首次报道了LiC分子几个低电子态在J=0下的振动能级、转动惯量和六个离心畸变常数(Dν,Hν,Lν,Mν,Nν和Oν). 相似文献
3.
Resonance Raman spectroscopic study for radial vibrational modes in ultra‐thin walled TiO2 nanotubes
Rajini P. Antony Arup Dasgupta Sudipta Mahana D. Topwal Tom Mathews Sandip Dhara 《Journal of Raman spectroscopy : JRS》2015,46(2):231-235
The study reports the observation of radial vibrational modes in ultra‐thin walled anatase TiO2 nanotube powders grown by rapid breakdown anodization technique using resonant Raman spectroscopic study. The as‐grown tubes in the anatase phase are around 2–5 nm in wall thickness, 15–18 nm in diameter and few microns in length. The Eg(ν1,ν5,ν6) phonon modes with molecular vibrations in the radial direction are predominant in the resonance Raman spectroscopy using 325 nm He–Cd excitation. Multi‐phonons including overtones and combinational modes of Eg(ν1,ν5,ν6) are abundantly observed. Fröhlich interaction owing to electron–phonon coupling in the resonance Raman spectroscopy of ultra‐thin wall nanotubes is responsible for the observation of radial vibrational modes. Finite size with large surface energy in these nanotubes energetically favor only one mode, B1g(ν4) with unidirectional molecular vibrations in the parallel configuration out of the three Raman modes with molecular vibration normal to the radial modes. Enhanced specific heat with increasing temperatures in these nanotubes as compared to that reported for nanoparticles of similar diameter may possibly be related to the presence of the prominent radial mode along with other energetic phonon mode. The findings elucidate the understanding of total energy landscape for TiO2 nanotubes. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
4.
The lowest infrared active perpendicular fundamental ν9 of disilane has been analysed on a Fourier transform spectrum between 320 and 430?cm?1, at the spectral resolution of 0.0012?cm?1. The rotation–torsion structure of this band is affected by x,y Coriolis interactions with excited torsional levels of the vibrational ground state, correlating with components of 3ν4 and 4ν4 in the high barrier limit. The interaction of ν9 and 4ν4, forbidden in the D3d symmetry limit, is allowed between components of E torsional symmetry under the G36(EM) extended molecular group, because of the large amplitude of the internal rotation motion. We could determine the values of the main vibration–rotation–torsion parameters of ν9, interaction parameters, and the vibrational wavenumbers of the four torsional components of 3ν4 and of the E3d component of 4ν4. The intrinsic torsional splitting of ν9 is found to be smaller than in the ground vibrational state by 0.0066?cm?1, in good agreement with our theoretical predictions. The possibility of observing the effects of D3d-forbidden interactions in the spectra of ethane-like molecules is also discussed. 相似文献
5.
The infrared spectrum of H2CCD2 was investigated in the region 2000-1200 cm?1 at a resolution of ~0.05 cm?1. Complete analyses of four type-A bands are reported-the CC stretch, ν2, the CH2 deformation, ν12, and the overtones of the CD2 and CH2 wagging fundamentals, 2ν7 and 2ν8. Localized perturbations are identified and taken into account in the analyses, enabling the perturbing vibrational levels to be located accurately and the interaction parameters to be determined. In the case of ν12, Fermi resonance with 2ν10 has a global effect, and causes a bandhead to be formed in the Ka subband series. 相似文献
6.
《Journal of Molecular Spectroscopy》1987,123(1):48-83
Stark spectra of OC34S, O13CS, and 18OCS have been recorded with an intracavity CO2 laser spectrometer. The observed transitions are the 2ν2 band and the associated hot bands from ν21, ν1, 2ν20, 2ν22, ν1 + ν21, 3ν21, and 3ν23. One line has also been observed in the 0001 ← 0200 band of OC34S. For each isotopic species of OCS, a global weighted least-squares analysis has been applied simultaneously on all available zero-field and Stark data, yielding coherent sets of rovibrational and electrical molecular parameters. From the equilibrium rotational constants we have deduced an improved equilibrium structure for the OCS molecule. 相似文献
7.
《Journal of Molecular Spectroscopy》1986,118(1):288-297
Fourier Transform infrared spectra of gaseous natural FClO3 and monoisotopic F35ClO3 have been recorded at 293 and 225 K with a resolution of 0.04 cm−1. Rotational J structure and, in part, K structure were resolved for the parallel fundamentals, combination bands, and overtones ν1, ν2, ν3, ν1 + ν2, ν1 + ν3, ν2 + ν3, 2ν1, 2ν2, and 2ν3. Band origins ν0, anharmonicity constants χij, and vibration-rotation interaction constants αiA and αiB have been determined. For F35ClO3, ν0 values are ν1 = 1063.238(6), ν2 = 716.814(6), and ν3 = 549.877(3) cm−1. No perturbation was found at the present level of accuracy. 相似文献
8.
H. Sarkkinen 《Journal of Molecular Spectroscopy》2004,226(1):45-56
A high-resolution infrared spectrum of DCCI has been measured in the regions of the bands of 2ν1, ν1+ν2, ν2+ν3, ν2+ν4, ν2+ν5, and ν4+ν5. Using these bands together with the spectra measured previously, the rovibrational states of 2ν1, ν1+ν2, ν1+ν3, ν1+ν4, ν1+ν5, ν1+2ν5, ν2+ν3, ν2+ν4, ν2+ν5, ν2+2ν5, ν3+ν4, ν4+ν5, and ν4+2ν5 have been analyzed. Various l-type and Fermi resonances have been taken into account in the analysis. In addition, the weak Coriolis resonance between the levels υ3=υ4=1 and υ4=2 has been considered. Accurate values for the molecular constants and the appropriate resonance parameters have been obtained. The unperturbed normal vibrational frequencies associated to the equilibrium state have been calculated for both isotopic species HCCI and DCCI. Then the harmonic force constants for monoiodoacetylene have been determined. 相似文献
9.
G. Di Lonardo L. Fusina A. Trombetti Ian M. Mills 《Journal of Molecular Spectroscopy》1982,92(2):298-325
The ir absorption of gaseous 15NH3 between 510 and 3040 cm?1 was recorded with a resolution of 0.06 cm?1. The ν2, 2ν2, 3ν2, ν4, and ν2 + ν4 bands were measured and analyzed on the basis of the vibration-rotation Hamiltonian developed by V. ?pirko, J. M. R. Stone, and D. Papou?ek (J. Mol. Spectrosc.60, 159–178 (1976)). A set of effective molecular parameters for the ν2 = 1, 2, 3 states was derived, which reproduced the transition frequencies within the accuracy of the experimental measurements. For ν4 and ν2 + ν4 bands the standard deviation of the calculated spectrum is about four times larger than the measurements accuracy: a similar result was found for ν4 in 14NH3 by ?. Urban et al. (J. Mol. Spectrosc.79, 455–495 (1980)). This result suggests that the present treatment takes into account only the most significant part of the rovibration interaction in the doubly degenerate vibrational states of ammonia. 相似文献
10.
《Journal of Molecular Spectroscopy》1987,126(2):290-306
The parameters of NH2D in the ground and ν2 states have been refined by a simultaneous analysis of the microwave, FTIR, and diode laser data. The intensities of 46 NH2D lines have been measured, and from a least-squares fit of the intensity data the a ← s, s ← a, s ← s, and a ← a transition moments have been derived. The intensities of the lines in the ν2 band of NH2D have been calculated taking into account the inversion-rotation interaction. The accuracies of the wavenumbers and intensities calculated with the new parameters are estimated to be better than ±0.0002 cm−1 and ±5%, respectively. The matrix elements for interaction of vibrations through x, y, and z axis couplings are appended. 相似文献
11.
Shui-Ming Hu O.N. Ulenikov E.S. Bekhtereva G.A. Onopenko Sheng-Gui HeHai Lin Ji-Xin ChengQing-Shi Zhu 《Journal of Molecular Spectroscopy》2002,212(1):89-95
The high-resolution absorption spectrum of the D2O molecule was recorded with the Fourier-transform intracavity laser absorption spectrometer in the region 12 570-12 820 cm−1 where the band 4ν1+ν3 is located. Transitions belonging to the 4ν1+ν3 band, and the bands 3ν1+2ν3 and 3ν1+2ν2+ν3, of which the up states are strongly interacted with that of the 4ν1+ν3, were assigned in the recorded spectrum. Up state energy levels were fitted to derive effective spectroscopic parameters, which reproduce majority of the assigned transitions within the experimental accuracy. 相似文献
12.
D.A. Steiner S.R. Polo T.K. McCubbin K.A. Wishah 《Journal of Molecular Spectroscopy》1983,100(2):453-454
The ν2 fundamental band of HNCO has been observed for the first time under a resolution of 0.015 cm?1. The band origin for this NCO antisymmetric stretching vibration is found to be at 2268.893 cm?1, rather distant from the previously reported value of 2274 cm?1. Nineteen subbands have been analyzed and term values for both ground and ν2 states with K up to 4 have been obtained. Effective rotational constants B and centrifugal distortion constants D and H have also been determined. Interactions are observed with 2ν4 + ν5 and ν3 + ν4. Large perturbations are observed for K = 0 and K = 1 levels of ν2. Transitions are also seen for three other vibrations, ν4 + ν5 + ν6, ν3 + ν6, and 2ν4 + ν6. 相似文献
13.
The Raman spectrum of polycrystalline cyclopropane between 3200 and 10 cm?1 has been recorded. All Raman active fundamentals, two other fundamentals ν4(A″1) and ν7(A″2), several new crystal components of fundamentals, and many new bands arising from overtones and combinations have been observed.The splittings of the fundamentals, together with the coincidences of infrared and Raman wavenumbers for both fundamentals and lattice modes, are consistent with a C2v factor group, a Cs site, and two molecules per orthorhombic unit cell. 相似文献
14.
Willes H. Weber 《Journal of Molecular Spectroscopy》1980,79(2):396-415
The rigid-bender model is used to treat the large-amplitude, low-frequency, bending vibration ν7 of C3O2. Different parameterizations of the bending potential function are considered, and a simple two-term power series is found to give the best fit. With this parameterization, using a least-squares fit to energies and B values, the ν7 potential function is determined for the ground state as well as for the states in which ν2, ν3, ν4, ν6, 2ν6, ν1 + ν3, ν1 + ν4, ν2 + ν3, and 2ν2 + ν4 are excited. The excitation of other vibrations has in some cases a drastic effect on the ν7 potential. In the ground state the potential has a 29 cm?1 barrier at the linear position, in ν1 + ν3 the barrier increases to 79 cm?1, while in 2ν2 + ν4 the barrier vanishes. An equilibrium potential is determined by correcting the ground state potential for the effects of zero-point motion of the normal vibrations ν1, …, ν6. This potential has a 35.6-cm?1 barrier with a minimum at α = 11.14°, where 2α is the angular deviation from linearity. The model accurately predicts the quartic and sextic centrifugal distortion terms for the low-lying v7ν7l7 states. Second-order l-type coupling is included in the calculations of the quartic terms. The effects of this coupling, which are most pronounced for the ν7 ≥ 2 states, adequately explain the negative D term recently reported for the ν2 + 4ν70 state. 相似文献
15.
Adriana Predoi-Cross Marco Brawley-Tremblay Linda R. Brown D. Chris Benner 《Journal of Molecular Spectroscopy》2006,236(2):201-215
Room temperature Lorentz air-broadened halfwidth and pressure-induced air-shift coefficients were measured for 1011 transitions in the octad region of methane between 4100 and 4635 cm−1. These measurements were made by analyzing 10 laboratory absorption spectra recorded at 0.011 cm−1 resolution using the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak, Arizona. The spectra were obtained using two absorption cells with path lengths of 2.05 and 150 cm. The total sample pressures ranged from 99 to 400 torr with CH4 volume mixing ratios of 0.01 in dry air. The spectral line parameters were retrieved using a multispectrum nonlinear least squares technique. Transitions belonging to five bands of the octad polyad were observed, namely ν2 + 2ν4, ν1 + ν4, ν3 + ν4, 2ν2 + ν4, and ν2 + ν3. The numbers of measurements by bands are: 33 for ν2 + 2ν4, 180 for ν1 + ν4, 635 for ν3 + ν4, 33 for 2ν2 + ν4, and 130 for ν2 + ν3. Transitions with rotational quantum number J up to 16 are included in the analysis. The measured width and shift coefficients vary according to the tetrahedral symmetry species and the rotational quantum numbers of the transitions. The retrieved parameters from this study are compared with prior results, in part to estimate absolute accuracy and determine the extent of vibrational dependence of widths and shifts. 相似文献
16.
《Molecular physics》2012,110(17):2091-2102
The dideuterated form of methyl bromide, CHD2Br, has been synthesized and the gas-phase infrared spectra investigated in the range 400–10,000?cm–1 using a medium-resolution FTIR spectrometer. The nine fundamental bands have been characterized in detail. Six of them, i.e. ν 1, ν 4, ν 5, ν 7, ν 8 and ν 9, have been rotationally analysed through the assignment of the partially resolved structure of the PQK and RQK cluster of lines and the spectroscopic parameters have been derived in the symmetric top limit approximation. Among the fundamental levels, anharmonic resonance occurs between ν 7/ν 4?+?ν 8 and ν 8/ν 6?+?ν 9. An isotopic 79/81Br shift was found for ν 6 and in the more complex region of the ν 8 fundamental. High-quality ab initio calculations – carried out at coupled cluster level [CCSD(T)] employing the correlation-consistent basis set of Dunning (cc-pVTZ) – were performed to determine quadratic, cubic and quartic (semidiagonal) force constants. Using these constants and applying second-order vibrational perturbation theory (VPT2), with allowance for resonances (when necessary), permitted us to identify and assign, in addition to the fundamentals, about 70 overtones and combination bands up to three quanta. 相似文献
17.
Fourier transform spectra recorded using (a) natural abundance water vapor, (b) H218O-enriched water vapor, and (c) H217O-enriched water vapor are analyzed. The ratio of intensities in three spectra is used to identify 927 lines due to absorption by H218O. Intensities and self-broadening parameters are derived for these lines. Using theoretical linelists, comparisons with previously assigned H216O spectra, and automatic searches for combination differences, 747 lines are assigned. These lines belong to 14 vibrational states in the 3ν+δ and 4ν polyads. Newly determined H218O vibrational band origins include 4ν1 at 13 793.09 cm−1, 3ν1+ν3 at 13 795.40 cm−1, 2ν1+2ν3 at 14 188.82 cm−1, ν1+3ν3 at 14 276.34 cm−1, and 2ν2+2ν2+ν3 at 13 612.71 cm−1. These results are compared with data in HITRAN. 相似文献
18.
Jens-Erik Lolck Svend Brodersen Alan G. Robiette 《Journal of Molecular Spectroscopy》1982,95(2):313-333
The purely isotropic Raman spectrum of the ν1 band, the ν2 + ν4 band (enhanced through interaction with ν1), and the 2ν2 band of 12CH4 was obtained with a spectral resolution of 0.30–0.35 cm?1 from exposures with different orientations of the linearly polarized exciting light. The ν2 + ν4 and 2ν2 bands show partially resolved rotational structure. The spectra are interpreted in terms of a model which takes explicitly into account vibrational and rovibrational interactions with other vibrational states, using molecular constants determined primarily from infrared spectra. The computed contours are in excellent agreement with the experimental ones and the observed and calculated peak wavenumbers agree within one tenth of the spectral resolution limit, except for a small region near the ν1 band. The good overall agreement represents an independent check on the overall correctness of the previously reported molecular constants. A detailed discussion is given of the contributions to the intensities of individual transitions from the three transition moment matrix elements, which in an isolated-band model are the intensity parameters of the ν1, 2ν4, and 2ν2 isotropic bands, respectively. 相似文献
19.
The infrared band ν4 of CD3I between 2220 and 2390 cm?1 has been investigated at a resolution of 5.4 × 10?3 cm?1. More than 2000 lines were assigned to subbands with KΔK from ?18 to 21, including J values up to 70. In the analysis the Coriolis resonances with ν3 + ν5±1 + ν6±1, ν2 + 2ν6±2, ν2 + 2ν60, and 2ν3 + 2ν6±2 were taken into account. The molecular constants concerning the fundamental ν4, as well as the parameters describing the combination levels, were derived. 相似文献
20.
S.A. Rackley R.J. Butcher M. Römheld S.M. Freund T. Oka 《Journal of Molecular Spectroscopy》1982,92(1):203-217
About 550 Stark tuned resonances of the ν4 and ν7 vibration-rotation bands of CH3CN were measured using 12CO2, 13CO2, and N2O lasers. These data are combined with 26 microwave measurements and fitted to a model which includes l-type doubling in ν7, ν4-ν7 Coriolis coupling, and ν7-3ν81 Coriolis and Fermi couplings. The infrared and microwave data can be reproduced with standard deviations of 7 MHz and 40 kHz, respectively. The many vibration-rotation parameters and the dipole moments are determined with great accuracy. A complete list of derived parameters is given in Table I. 相似文献