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1.
Resonance photoelectron spectra of methyl iodide have been taken by exciting individual autoionizing Rydberg states, and measuring the ejected electron energies by a time of flight technique. A number of spectra were obtained from autoionization states which are members of two series, converging respectively to the 2E (ν = 0) and 2E (ν2 =1) states of the ion. In addition to observing vibrational bands not previously reported, we found that the peak intensities are consistent with Bardsley's formulation of the configuration interaction theory of autoionization. 相似文献
2.
The transitions J = 1 ← 0, K = 0; J = 2 ← 1, K = 0; and J = 2 ← 1, K = 1 of CH3I and CD3I were measured using a Stark-modulated microwave spectrometer. Iodine quadrupole coupling strengths were analyzed to determine variations with deuterium substitution on the methyl group and variations with centrifugal distortion. Quadrupole coupling strengths were described by the expression . Explicit expressions are given for a, b, and c for a symmetric top in terms of molecular parameters. For CH3I eQq0 = ?1934.11 ± 0.02 MHz and for CD3I eQq0 = ?1928.95 ± 0.04 MHz. Rotational constants obtained are B(CH3I) = 7501.274 ± 0.002 MHz and B(CD3I) = 6040.298 ± 0.007 MHz. The observed fractional change in halogen quadrupole coupling of 0.0027 is related to previous results for methyl chloride and methyl bromide. 相似文献
3.
Measurements of the absolute vibrational Raman intensities and depolarization ratios for the fundamental and some overtone and combination bands of CH4, CH3D, CH2D2, CHD3, and CD4 are reported. Experimental aspects of these measurements are discussed. The experimental data conform satisfactorily to all isotope intensity sum rules. The measured intensities and depolarization ratios, together with the vibrational potential function for CH4, make possible the calculation of the four independent parameters of the isotopic invariant quantities . The results deduced from these agree with all 36 experimentally observed values. Values of electro-optical parameters for the CH bond are calculated and discussed. 相似文献
4.
The multiplet splitting patterns of microwave transitions in the ground state and the first two torsional excited states of CH3OCH3, CD3OCD3, and CD3OCH3 were analyzed in terms of the semirigid rotor models C2vF-C3vT-C3vT and . The following nonzero potential coefficients were obtained for CH3OCH3: V30 = V03 = 909.05 ± 0.49 cm?1, V′33 = 5.06 ± 1.60 cm?1; for CD3OCH3: V30(CD3) = 897.18 ± 2.41 cm?1, V03(CH3) = 910.45 ± 0.33 cm?1; for CD3OCD3: V30 = V03 = 897.00 cm?1. These results are compared to earlier microwave studies of these molecules. 相似文献
5.
The J = 1 ← 0 and J = 2 ← 1 transitions and the l-doubling transitions of J = 2 – 6 of 12CH3F in the ν2 and ν5 states were analyzed by taking into account the Coriolis interaction between the two modes. The molecular constants which are derived are: ν5 - ν2, 252 412 ± 112; , 25 611.60 ± 0.40; Aζ5, ?38 772 ± 116; , 25 432.52 ± 0.33; D, 21 838.4 ± 8.2; , 39.58 ± 0.30 MHz; in addition to a few other minor constants. The present result is completely consistent with the recent Raman data of Escribano, Mills, and Brodersen, J. Mol. Spectrosc.61, 249 (1976). Molecular constants in the ν3 and ν6 states have also been obtained: B3, 25 197.570 ± 0.020; B6, 25 418.917 ± 0.047; Aζ6ηJ, ?0.562 ± 0.030; |q6|, 8.70 ± 0.13 MHz. Errors are 2.5 times the standard deviations. 相似文献
6.
Jon T. Hougen 《Journal of Molecular Spectroscopy》1984,106(1):134-154
Rotational energy levels in vibronic ground states of 2A, 2E, and 2F electronic states of open-shell XY4 molecules, as well as rotational line intensities for allowed transitions between such states, are discussed, including the effects of spin-orbit interaction and tetrahedral splittings. Jahn-Teller effects are assumed to be small, and are only taken into account implicitly, through their contributions to various parameters in the effective Hamiltonian. Qualitative information is obtained by considering several limiting-case coupling schemes among the electron spin angular momentum S, the electron orbital angular momentum L, and the pure rotational angular momentum R. These limiting cases are similar in spirit to Hund's coupling cases in diatomic molecules, but differ sufficiently from the latter to make detailed correspondences unhelpful. Quantitative information on rotational energy levels and line intensities is obtained numerically by diagonalizing a Hamiltonian matrix set up in a basis set characterized by uncoupled moleculefixed projections of S, L, and the total angular momentum J, and symmetrized so that all basis set functions belong to a definite species in the subgroup D2d of the true point group Td. Hamiltonian matrix elements are determined by ladder operator techniques. Three sample calculated spectra, corresponding to , , and are presented. As one might expect, when the spin-orbit constant A is set equal to zero, then both qualitative and quantitative aspects of the rotational-electronic problem in open-shell XY4 molecules can be mapped easily onto discussions of the rotation-vibration problem from the CH4 literature. 相似文献
7.
P. B. Davies Yuyan Liu Zhuan Liu 《International Journal of Infrared and Millimeter Waves》1993,14(12):2395-2400
Twenty-seven new cw far infrared laser lines with wavelengths between 137 and 988m have been observed from optically pumping C2H3F, C2H3Cl, C2H3Br, C2H5F, C2H3CN, CH2CF2, HCOOH and CH3Br with a CO2 laser. The wavelengths of these FIR laser lines were determined together with their optimum pressures and relative intensities. 相似文献
8.
The microwave spectrum of MnO3F has been remeasured and several corrections and new results have been obtained: B0 = 4129.141 MHz, DJ = 1.12 kHz, DJK = 1.87 kHz; , , , |q5| = 16.005, and |q6| = 8.456 MHz. 相似文献
9.
10.
Second order elastic constants of NH4Cl and NH4Br crystals were measured under hydrostatic and uniaxial pressures near the λ-type phase transitions. Third order elastic constants were calculated from the pressure derivatives of the second order elastic constants. Results show that the temperature dependences of the third order elastic constants of NH4Cl differ from those of NH4Br dramatically. In addition, it is found that the coefficients and of strains in the free energy of NH4Cl show quite different temperature dependences from those of NH4Br. 相似文献
11.
Measurements of the dielectric constants revealed a ferro- to paraelectric transition in methylammonium trichloromercurate (CH3NH3HgCl3). Thermal analysis by differential scanning calorimetry indicates a transition temperature of Tc ≈ 60°C. The structures of both phases were determined from single crystal X-ray measurements. The ferroelectric phase crystallizes at room temperature in the polar trigonal space group . The refinement of the ferroelectric structure included the fractional contribution of the two domains present. The paraelectric phase has monoclinic symmetry (space group C2 with and contains an almost completely disordered methylammonium group while order with pronounced thermal motion is observed in the ferroelectric phase. 相似文献
12.
S.M. Freund G. Duxbury M. Römheld J.T. Tiedje T. Oka 《Journal of Molecular Spectroscopy》1974,52(1):38-57
Laser Stark spectroscopy of the ν3 band of CH3F has been carried out using coincidences with the 9.4 μm band CO2 laser lines. About 350 Stark resonances were measured for the ν3 fundamental bands of 12CH3F and 13CH3F. About 30 of them were measured by using a Stark-Lamb dip technique to increase the resolution and the accuracy of the data. These Stark resonances, together with the recent results of infrared-microwave two-photon Lamb dip measurements, were analyzed to give the following vibration-rotation parameters and the dipole moments in the ν3 state,
12CH3F | 13CH3F | ||
1048.610767 (62) | 1027.493191 (69) | cm?1 | |
25197.57 ± 0.03 | 24542.07 ± 0.43 | MHz | |
?294.09 ± 0.60 | ?288.81 ± 0.37 | MHz | |
55.5 ± 1.2 | 56 ± 12 | kHz | |
575 ± 63 | 464 ± 24 | kHz | |
μ | 1.9054 ± 0.0006 | 1.9039 ± 0.0006 |