Knowledge Bank

The $\upsilon 3+\upsilon 4$ bands of $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CH4$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}CH4$ are analyzed from high resolution F.T. spectra, and on the basis of the tetrahedral theory and extrapolation method which has been developed in DIJON (1). In the case of $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CH4$, the analysis has been extended from J' = 7 to J' =10, using assignments of previous works (2, 3). In the case of $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}CH4$, the work is the first comprehensive study of this band. In both cases. a set of $25\upsilon 3+\upsilon 4$ parameters have been determined whereas the ground-state, $\upsilon 3$ and $\upsilon 4$ constants were held fixed. In both cases, more than 1000 lines have been assigned and about 750 of them were used in the determination of the 25 parameters. The obtained standard deviations are less than $0.05cm-1$. These results will be discussed together with the detected anomalies in view of a complete study of the spectrum of methane in the $2.3\mu$ region and in view of the $\upsilon 3+\upsilon 4-\upsilon 4$ study in the $3\mu$ region.