Sari-Zizi NB, Najib H, Sebihi R, Pracna P
Faculté des Sciences, Université Mohammed V, Rabat (Agdal), B.P. 1014, Morocco
J Mol Spectrosc. 1998 Jul;190(1):15-27. doi: 10.1006/jmsp.1998.7568.
With a resolution of 4.4 x 10(-3) cm-1, we were able to identify in this range the very weak nu2 + 2nu04 (A1) component near 1180 cm-1, the nu3 + nu4 band around 1205 cm-1 with its (A1 + A2) and E very intermixed components, and the nu1 + nu4 (E) band centered at 1238 cm-1. Three thousand six hundred transitions belonging to the (nu3 + nu4, nu1 + nu4) interacting system were fitted together with a model taking into account l(2, 2) interactions inside nu1 + nu4 and between (A1 + A2) and E components of nu3 + nu4, the l-vibrational resonance inside nu3 + nu4(A1 + A2), and the Coriolis interactions between nu1 + nu4 and nu3 + nu4(A1 + A2) on one hand and between nu1 + nu4 and nu3 + nu4 (E) on the other. Four available MW transitions were also included in the fit. A rms of 0.76 x 10(-3) cm-1 was obtained with 34 free parameters among 38. Normally the Fermi resonance, which links nu3 to nu2 + nu4 with a coupling term W234 = 2.86 cm-1, must connect each component of nu3 + nu4 with each component of nu2 + 2nu4. But since we have only little experimental information about the weak nu2 + 2nu04 component (120 assigned lines) and none about the dark nu2 + 2nu+/-24 component, it was not possible to introduce this resonance in the fit. However, the bandcenters' shifts were calculated since the basic coupling term W234 and the anharmonic constant x24 are well known. Therefore, according to this approximation, the very sensitive anharmonic constants x34 and g34 could be deduced. Of course the x14 Fermi-independent constant, derived directly from the (nu1 + nu4)0 bandcenter given by the fit, was certainly more accurate. Copyright 1998 Academic Press.
分辨率为4.4×10⁻³厘米⁻¹时，我们能够在该范围内识别出1180厘米⁻¹附近非常弱的ν₂ + 2ν₀₄（A₁）分量、1205厘米⁻¹附近的ν₃ + ν₄带及其（A₁ + A₂）和E非常混合的分量，以及以1238厘米⁻¹为中心的ν₁ + ν₄（E）带。属于（ν₃ + ν₄，ν₁ + ν₄）相互作用体系的3600个跃迁与一个模型一起拟合，该模型考虑了ν₁ + ν₄内部以及ν₃ + ν₄的（A₁ + A₂）和E分量之间的l（2, 2）相互作用、ν₃ + ν₄（A₁ + A₂）内部的l - 振动共振，以及一方面ν₁ + ν₄与ν₃ + ν₄（A₁ + A₂）之间、另一方面ν₁ + ν₄与ν₃ + ν₄（E）之间的科里奥利相互作用。拟合中还包括了4个可用的微波跃迁。在38个参数中有34个自由参数的情况下，均方根为0.76×10⁻³厘米⁻¹。通常，将ν₃与ν₂ + ν₄联系起来且耦合项W₂₃₄ = 2.86厘米⁻¹的费米共振，必须将ν₃ + ν₄的每个分量与ν₂ + 2ν₄的每个分量连接起来。但由于我们关于弱ν₂ + 2ν₀₄分量（120条指定谱线）的实验信息很少，且关于暗ν₂ + 2ν₊/₋₂₄分量没有任何信息，所以无法在拟合中引入这种共振。然而，由于基本耦合项W₂₃₄和非谐常数x₂₄是已知的，所以计算了带中心的位移。因此，根据这种近似，可以推导出非常敏感的非谐常数x₃₄和g₃₄。当然，直接从拟合给出的（ν₁ + ν₄）₀带中心得出的与费米无关的常数x₁₄肯定更准确些。版权所有1998年学术出版社。
