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1.
R Anttila J Kauppinen M Huhanantti T Kärkkäinen 《Journal of Molecular Spectroscopy》1977,64(3):460-473
The bending vibration bands ν4 and ν5 of HCCI were studied. From the observed rotational structure the rotational constant B0 and the centrifugal distortion constant D0 were obtained. The results were B0 = 0.105968(7) cm?1 and D0 = 1.96(7) × 10?8 cm?1 from ν4 and B0 = 0.105948(8) cm?1 and D0 = 1.96(11) × 10?8 cm?1 from ν5. The structure of the hot bands 2ν5(Δ) ← ν5(Π) and 3ν5(φ) ← 2ν5(Δ) was also resolved and hence the values α5 = ?3.033(8) × 10?4 cm?1 and q5 = 9.3(3) × 10?5 cm?1 could be derived. The other most intense hot bands following ν5 could be explained in terms of the Fermi diads and . Of the numerous hot bands accompanying ν4, only those between different excited states of ν4 could be assigned. Then estimates for α4 and q4 were also obtained. In addition, several vibrational constants were derived. 相似文献
2.
A high-resolution infrared spectrum of methane-d2 has been measured in the C-D stretching band region (2025–2435 cm?1). Rotational structures of the ν2 and ν8 bands have been assigned by use of the ASSIGN-diagram method, and the c-type Coriolis interaction between ν2 and ν8 has been analyzed. The band origins, ν2 = 2203.22 ± 0.01 cm?1 and ν8 = 2234.70 ± 0.01 cm?1, the rotational constants and the centrifugal distortion constants for the two bands, and the Coriolis coupling constant, , have been determined. 相似文献
3.
The gas phase infrared spectra of monoisotopic H3Si35Cl and H3Si37Cl have been studied in the region near 2200 cm?1 with a resolution of 0.012 and 0.04 cm?1, respectively, and rotational fine structure for ΔJ = ±1 branches has been resolved. In addition, some information on ν3 + ν4 of H3Si35Cl near 2750 cm?1 has been obtained. ν1 and ν4 are weakly coupled by Coriolis x, y resonance, , only the upper states K′ = 2, l = 0 and K′ = 1, l = ?1 being substantially affected. Local perturbation due to rotational l(±1, ±1)-type resonance with ν3 + ν5+1 + ν6+1 and ν3 + ν5+1 + ν6?1 is revealed in the ΔK = +1 and ?1 branches, respectively. From a fit of the experimental line positions, standard deviations of 1.4 and 3.8 × 10?3 cm?1, respectively, to a model with five interacting levels conventional excited state parameters and interaction constants have been obtained. In the fundamentals are ν1, and ν4, , respectively. Q branches of the “hot” band (ν3 + ν4) ? ν3 and of ν4 of the 29Si and 30Si species have been detected. 相似文献
4.
L Nemes 《Journal of Molecular Spectroscopy》1978,72(1):102-123
Medium resolution infrared grating spectra of gaseous ketene, H2CCO were recorded between 1000 and 400 cm?1, both at instrument temperature (40°C) and with cooling (?40°C). Interferometric Fourier spectra were also measured at ?70°C with resolution 0.22 cm?1 between 450 and 330 cm?1. The K structure of the fundamentals ν5, ν6, ν8, and ν9 was assigned. These fundamentals are coupled by a-axis Coriolis interactions. These couplings were analysed on the symmetric top basis for setting up the perturbation matrix and by utilizing the K-dependent Coriolis shifts of levels. A preliminary analysis of the Coriolis intensity anomalies was also undertaken.Band center values from combination differences are and . Synthetic spectra indicate the band origins of ν8 and ν9 to be close to 977.8 and 439.0 cm?1, respectively. Estimates of Coriolis coupling constants obtained from synthetic spectra are , , , and . Approximate ratios of unperturbed vibrational transition moments obtained from spectral simulations are . 相似文献
5.
V Malathy Devi B Fridovich G.D Jones D.G.S Snyder 《Journal of Molecular Spectroscopy》1983,97(2):333-342
Line strengths and self- and nitrogen-broadened half-widths were measured for spectral lines in the ν3 and ν2 + ν4 bands of 12CH4 and 13CH4 from 2870–2883 cm?1 using a tunable diode laser spectrometer. From measurements made over a temperature range from 215 to 297 K, on samples of 12CH4 broadened with N2, we deduced that the average temperature coefficients n, defined as , of the Lorentz broadening coefficients for the ν3 and ν2 + ν4 bands of 12CH4 were 0.97 ± 0.03 and 0.89 ± 0.04, respectively. A smaller increase is observed in line half-width with increasing pressure for E-species lines, for both self- and nitrogen-broadening, than for other symmetry species lines over the range of pressures measured, 70 to 100 Torr. 相似文献
6.
The vapor phase absorption spectrum of thiophosgene (Cl2CS) in the 2500–2900 Å region consists of a broad intense band (. On the red side of this a vibrationally discrete structure is found which becomes increasingly diffuse and merges into the broad band as the wavelength is decreased. It is shown that this vibrational structure can be explained as due to a , electronic transition between a planar ground state and a pyramidal excited state of the molecule. In the latter state, the CS stretching mode ν1′(a1) = 681 cm?1 and the CCl bending mode ν3′(a1) = 147 cm?1. From the inversion doublet splitting of the out-of-plane mode ν4′(b1), the barrier to inversion is calculated to be ~126 cm?1, with an equilibrium out-of-plane angle of ~20°. 相似文献
7.
A weak emission spectrum of I2 near 2770 Å is reanalyzed and found to to minate on the A(1u3Π) state. The assigned bands span v″ levels 5–19 and v′ levels 0–8. The new assignment is corroborated by isotope shifts, band profile simulations, and Franck-Condon calculations. The excited state is an ion-pair state, probably the 1g state which tends toward . In combination with other results for the A state, the analysis yields the following spectroscopic constants: T″e = 10 907 cm?1, ″e = 1640 cm?1, ω″e = 95 cm?1, ; T′e = 47 559.1 cm?1, ω′e = 106.60 cm?1, . 相似文献
8.
K.K. Innes 《Journal of Molecular Spectroscopy》1982,96(2):331-335
Approximate experimental and theoretical information about vibronic coupling of the (ground) and electronic states of NO2—by its antisymmetric vibration ν3(b2)—is tested in model calculations of the accurately known ground-state levels ν3 = 0, 1, 2, 3. The test is positive and it is estimated that 64% of the very large observed anharmonic constant χ33 has its origin in vibronic coupling. In this model, ν3 in the à state is predicted at about 1200 cm?1. 相似文献
9.
The 276-nm absorption band system () of m-dichlorobenzene was photographed under high resolution. The electronic origin band (0, 0) and a band at (0 + 380) cm?1 were subjected to rotational “band contour” analysis. As a result, it is found that the origin band has a type A band contour and that at (0 + 380) cm?1 exhibits a type B band contour. The band contour analysis also yields an accurate determination of the excited state parameters, viz., A′ = 0.0911 ± 0.0003, B′ = 0.02852 ± 0.00005, and C′ = 0.02175 ± 0.00001 cm?1. A model geometry for the molecule m-DCB in its first excited singlet state has been proposed. 相似文献
10.
C Betrencourt-Stirnemann G Graner D.E Jennings W.E Blass 《Journal of Molecular Spectroscopy》1978,69(2):179-198
Previous studies of the parallel bands 2ν2 and of CH3Br by the two first authors have been completed by the analysis of the weaker perpendicular band ν2 + ν5, centered near 2745 cm?1. It is well known that the v2 = 1 and v5 = 1 states of methylbromide are linked by an x-y-type Coriolis interaction. Therefore, in the 2500–2900-cm?1 range, the levels are linked by a similar interaction. Least-squares and prediction programs have been written to treat this kind of problems and they have been satisfactorily applied to both isotopic species, CH379Br and CH381Br. A localized resonance in the K = 0 subband of ν2 + ν5 has been shown to be due to the 3ν3 + ν6 band. No evidence for a strong Fermi resonance between ν1 and has been found. 相似文献
11.
Yasuki Endo Shuji Saito Eizi Hirota Toshio Chikaraishi 《Journal of Molecular Spectroscopy》1979,77(2):222-234
Microwave spectra of SF2 in the first excited states of the three normal modes were observed and analyzed. A comparison of the observed inertia defects in the ν1 and ν3 states with those calculated by omitting the contributions of the Coriolis interaction between the two modes led to a vibrational frequency differences of 25.72 ± 0.33 cm?1, with ν1 being definitely higher. The inertia defect in the ground state and our measured values for the inertia defect in the ν2 state and for the difference were combined with the centrifugal distortion constants of Kirchhoff et al. [J. Mol. Spectrosc.48, 157–164 (1973)] to improve the harmonic force field. The interaction constant between the two SF stretching coordinates was determined precisely. The third-order and the cubic anharmonic potential constants were calculated from the observed vibration-rotation constants. The equilibrium structure was determined to be and θe(FSF) = 98.048 ± 0.013°. 相似文献
12.
The ν2(e) and ν3(f2) Raman spectra and the 2ν3 infrared spectrum of gaseous GeD4 have been observed and analyzed. The new data have been combined with those of the ν3(f2) infrared band to derive an improved set of rovibrational constants. The analysis yields B0 = 1.3544 ± 0.0010 cm?1 and . 相似文献
13.
From the angular distributions of γ-rays emitted by oriented 129gTe and 129mTe nuclei implanted in iron by isotope separator, unique spin assignments could be made for the excited states of 129I at 487.4 keV , 696.0 keV , 729.6 keV , 768.9 keV , 1050.4 keV and 1111.8 keV . In addition, E2/M1 amplitude ratios for the following 129I γ-rays (energies are in keV) are derived: δ(459.6) = ?(0.076+0.037?0.148); δ(487.4) = 0.50+0.17?0.10 or δ? = 0.35+0.15?0.09; δ(556.7) = 0.06±0.02 or δ? = ?(0.10±0.02); δ(624.4) = 0.10±0.26 or δ? > 0.4; the 696.0 keV γ-ray is pure E2; δ(729.6) = ?(0.34±0.06) or δ?1 = 0.55±0.05; δ(741.1) = ?(0.27±0.10) or δ?1 = ?(0.43±0.12); δ(817.2) = 0.46±0.04 or δ?1 =0.20±0.03 if ; δ(1022.6) = ?(0.02 ±0.02) or δ?1 = ?(0.23±0.02); ; δ(1111.8) = 0.06±0.05 or δ?1 = ?(0.08±0.05). The anisotropy of the 531.8 keV γ-ray excludes as a possible spin assignment for the 559.6 keV level, so that no level is fed in the decay from 129Te. Anisotropies for the 209, 250.7, 278.4 and 281.1 keV γ-rays are also measured. Comparison of the level scheme is made with theoretical predictions from both the pairing-plus-quadrupole model and the intermediate coupling unified model. 相似文献
14.
A millimeter-wave spectrometer having a sensitivity of 4 × 10?10 cm?1 in the 2-mm region has been constructed for observation of extremely weak millimeter-wave spectra of gases. It has been used to measure J → J, K = 0 ← 3 transitions in PH3 and J → J, K = 0 ← 3 as well as K = ±1 ← ±4 transitions in PD3. The B0 and C0 spectral constants (in MHz) are: for PH3, B0 = 133 480.15 ± 0.12 and C0 = 117 488.85 ± 0.16; for PD3, B0 = 69 471.10 ± 0.03 and C0 = 58 974.37 ± 0.05. The effective ground-state values obtained for the bond angle and bond length are: for PH3, and ; for PD3, and . The corresponding zero-point-average values were calculated to be: for PH3, and ; for PD3, and . For both species, the equilibrium values are and . 相似文献
15.
M.A. Mélières M. Chenevier F. Stoeckel 《Journal of Quantitative Spectroscopy & Radiative Transfer》1985,33(4):337-345
Quantitative measurements of intensities and widths were made for individual rotational lines of the atmospheric oxygen γ band by using a recently developed, highly sensitive, intracavity laser-absorption spectroscopic technique (ICLAS) at 300 torr m. The total band intensity derived from the line intensities is (STP). Self-broadening collision coefficients for the PP and PQ branch lines have been determined from the absorption line width and were found to vary from 0.055 cm?1 atm?1 at N″ = 1 to 0.037 cm?1 atm?1 at N″ = 27. 相似文献
16.
The phosphorescence spectrum of C3S2 was observed in a low-temperature Ar matrix with excitation of an Ar+ laser. The spectrum consists of a very strong 0-0 band at 18 287 cm?1 and well-resolved progressions in the ν2, ν5, ν6, and ν7 vibrations. Side bands were found on the high-energy sides of some transitions. The separation between the main and side bands is 23 cm?1. Polarization analysis suggests that C3S2 is linear symmetric in the Phosphorescent state as in the ground electronic state. On the basis of symmetry considerations and a qualitative evaluation of spin-orbit coupling, the phosphorescent state is assigned to 3Σu? with Σu+ and Πu components split by spin-spin interaction. The Σu+ level is lower than the Πu one by 23 cm?1 and the main and side band emissions start from the Σu+ and Πu levels, respectively. The Σu+ component seems to acquire allowed character from a 1Σu+ state by spin-orbit coupling and from bent and states by ν5 vibronic coupling. Mixing of the Σu+ and Πu components through ν5 is responsible for most of the side bands. The ν5 frequency is estimated to be 160 ± 20 cm?1 in the 3Σu? state from the intensities of ν5 progression bands and from the ground-state frequency, 411 cm?1. 相似文献
17.
The 0-0, 1-1, 2-2, and 3-3 bands of the A2Π-X2Σ+ transition of the tritiated beryllium monohydride molecule have been observed at 5000 Å in emission using a beryllium hollow-cathode discharge in a He + T2 mixture. The rotational analysis of these bands yields the following principal molecular constants. From the pure electronic energy difference (EΠ - EΣ)BeT = 20 037.91 ± 1.5 cm?1 and the corresponding previously known values for BeH and BeD, the following electronic isotope shifts are derived and related to the theoretical approach given by Bunker to the problem of the breakdown of the Born-Oppenheimer approximation. 相似文献
18.
The sound velocities in GeS2 glass have been measured by means of ultrasonic interferometry as a function of temperature or pressure up to 1.8 kbar. The bulk modulus Ks = 117.6 kbar and shear modulus G = 60.60 kbar were obtained for GeS2 glass at 15°C and 1 atm. The temperature derivatives of both sound velocities and elastic moduli are negative : p = °C, p = °C and p = , p = ?1.23 × 10?2 kbar/°C, p = ?2.93 × 10?2 their pressure derivatives are positive: T = 4.43× 10?2km/kbar, T = and (?Ks?P0)T=6.81, = 1.03, (?Y?TT= 3.57. The Grüneisen parameter, γth= 0.298, and the second Grüneisen parameter, δs = 3.27, have also been calculated from these data. The elastic behavior of GeS2 glass has proved to be normal despite the structural similarity among the tetrahedrally coordinated SiO2, GeO2 and GeS2 glasses. 相似文献
19.
Kentarou Kawaguchi Chikashi Yamada Yoshiaki Hamada Eizi Hirota 《Journal of Molecular Spectroscopy》1981,86(1):136-142
The fundamental bands of the CF radical in the and electronic states were observed by using an infrared tunable diode laser as a source. Zeeman modulation could be used in detecting lines not only in the state, but also in , because the CF radical deviates considerably from Hund's case (a). From the least-squares analysis of the observed spectra, the following molecular constants were obtained: Be = 1.416 704 (37) cm?1, αe = 0.018 419 (50) cm?1, , De = 6.68 (15) × 10?6cm?1, p0 = 0.008 580 (21) cm?1, p1 = 0.008 52 (11) cm?1, and , with three standard errors in parentheses. 相似文献
20.
Taisuke Nakanaga Shigeo Kondo Shinnosuke Saëki 《Journal of Molecular Spectroscopy》1980,81(2):413-423
The Coriolis interactions between ν1 and ν3, and between ν2 and ν3 in SO2 have been analyzed to obtain the signs of the products and . It has been found that both of the signs of these products are positive. Then, relative signs of () have been determined using the calculated values of the Coriolis zeta constants for the present definition of the normal coordinates. The obtained sign combination of () is ±(+?+), which agrees with the one predicted by the molecular orbital calculations. Using the sign combination (+?+), the polar tensors of S and O atoms were also calculated. 相似文献