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1.
The high-resolution Fourier transform infrared spectrum of phosphorus trifluoride PF3 have been reinvestigated in the ν4 perpendicular band region around 347 cm−1. Thanks to recent pure rotational measurements, 595 new infrared transitions of the ν4 band have been assigned extending the rotational quantum number values up to Kmax = 66 and Jmax = 67. As a consequence of this extension, a sophisticated model containing a large number of parameters and interaction constants was adopted for the analysis of the IR transitions of the ν4 fundamental band of PF3. A merge of the IR transitions and the reported MW/MM/RF data within the v4 = 1 excited level yielded an accurate rotational ground state C0 value, 0.159970436 (69) cm−1, which was used to determine an improved GS structure, r0(P-F) = 1.56324405 (11) Å and ?(FPF) = 97.752232 (29)°. All experimental data have been refined applying various reduction forms of the effective rovibrational Hamiltonian developed for an isolated degenerate state of a symmetric top molecule. The v4 = 1 excited state of the PF3 oblate molecule was treated with models taking into account ?- and k-type intravibrational resonances. Parameters up to sixth order have been accurately determined and the unitary equivalence of the derived parameter sets in different reductions was demonstrated. 相似文献
2.
Geoffrey DuxburyAlexander Alijah 《Journal of Molecular Spectroscopy》2002,211(1):31-57
The extended stretch-bender Hamiltonian, incorporating spin-orbit coupling and overall rotation, has been used to calculate the spin-vibronic structure of the rovibronic energies in the region where the vibronic states of the excited Ã2A1 electronic state of NH2 interact with near-resonant high-lying levels of the X?2B1 state of NH2. A detailed comparison has been made with the experimental measurements which were made of these rovibronic states, the majority of which are due to Ramsay, Vervloet, and their collaborators. We have shown that, as in our study of the vibronic levels of the X?2B1 state below the barrier to linearity, in order to fit the variation of the effective vibronic spin-orbit coupling constant over the whole of this energy regime, the effective linear molecule spin-orbit coupling constant, ASO must be increased from the earlier value of 50 cm−1 of Ch. Jungen, K.-E. J. Hallin, and A. Merer (Mol. Phys.40, 65-94 (1980)) to 61.6 cm−1. The impact of Fermi resonance, in both the Ã2A1 and X?2B1 states, on the observed rovibronic structure has been assessed. The pattern of calculated spin-rovibronic levels, including the effects of spin uncoupling, is in good agreement with that measured experimentally. 相似文献
3.
Vibration-rotation transitions of diacetylene between the first excited states of the ν6 (CCH symmetric bending) and the ν8 (CCH antisymmetric bending) vibrations were observed with a Stark modulation microwave spectrometer. The rotational, centrifugal distortion and l-type doubling constants of the two vibrational states were determined as follows with 2.5 σ uncertainties in parentheses.
4391.3230(84) | 0.582(154) | 2.4830(32) | ||||
4391.1921(94) | 0.594(179) | 2.4073(37) |
35ClO2 | 37ClO2 | |||||
945.592 357(60) | 939.602 909(66) | cm?1 | ||||
μ′ | 1.788 39(13) | 1.788 46(15) | D | |||
μ″ | 1.791 95(10) | 1.792 10(13) | D | |||
δμ | ?0.003 56(18) | ?0.003 64(26) | D |
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