Ouardi O, Hilico JC, Loete M, Brown LR
Laboratoire de Physique de l'Universite de Bourgogne, Dijon Cedex, F-21004, France
J Mol Spectrosc. 1996 Dec;180(2):311-22. doi: 10.1006/jmsp.1996.0254.
Experimental line intensities of 1727 transitions arising from nine hot bands in the pentad-dyad system of methane are fitted to first and second order using the effective dipole moment expansion in the polyad scheme. The observed bands are nu3 - nu2, nu3 - nu4, nu1 - nu2, nu1 - nu4, 2nu4 - nu4, nu2 + nu4 - nu2, nu2 + nu4 - nu4, 2nu2 - nu2, and 2nu2 - nu4, and the intensities are obtained from long-path spectra recorded with the Fourier transform spectrometer located at Kitt Peak National Observatory. For the second order model, some of the 27 intensity parameters are not linearly independent, and so two methods (extrapolation and effective parameters) are proposed to model the intensities of the hot bands. In order to obtain stable values for three of these parameters, 1206 dyad (nu4, nu2) intensities are refitted simultaneously with the hot band lines. The simultaneous fits to first and second order lead to rms values respectively of 21.5% and 5.0% for the 1727 hot band lines and 6.5% and 3.0% for the 1206 dyad lines. The band intensities of all 10 pentad-dyad hot bands are predicted in units of cm-2 atm-1 at 296 K to range from 0.931 (for 2nu4 - nu4) to 7.67 x 10(-5) (for 2nu4 - nu2). The total intensities are also estimated to first order for two other hot band systems (octad-pentad and tetradecad-octad) that give rise to weak transitions between 5 and 10 μm.
利用多组方案中的有效偶极矩展开式，对甲烷五元组 - 二元组系统中九个热带产生的1727条跃迁的实验谱线强度进行了一阶和二阶拟合。观测到的谱带为ν3 - ν2、ν3 - ν4、ν1 - ν2、ν1 - ν4、2ν4 - ν4、ν2 + ν4 - ν2、ν2 + ν4 - ν4、2ν2 - ν2和2ν2 - ν4，其强度是通过位于基特峰国家天文台的傅里叶变换光谱仪记录的长路径光谱获得的。对于二阶模型，27个强度参数中的一些不是线性独立的，因此提出了两种方法（外推法和有效参数法）来模拟热带的强度。为了获得其中三个参数的稳定值，将1206条二元组（ν4，ν2）强度与热带谱线同时重新拟合。对一阶和二阶的同时拟合分别导致1727条热带谱线的均方根值为21.5%和5.0%，1206条二元组谱线的均方根值为6.5%和3.0%。预测了所有10个五元组 - 二元组热带在296 K时的谱带强度，单位为cm-2 atm-1，范围从（2ν4 - ν4的）0.931到（2ν4 - ν2的）7.67×10-5。还对另外两个热带系统（八元组 - 五元组和十四元组 - 八元组）的总强度进行了一阶估计，这两个系统在5至10μm之间产生弱跃迁。
