Knowledge Bank

Stimulated Emission Pumping (SEP) has been used to detect the bending vibrational overtones of $a¯1A1CH2(\nu 2=2,3$, and 4). The vibrational term values and rotational constants, were determined. Comparison between the bending potential model calculations$\mathrm{<mrow\; data-mjx-texclass="ORD">1,2</mrow>}$ and experimental results places the barrier height of the bending motion for $a¯1A1CH3$ at about $9800cm-1$ and the $a¯$ and $b¯$ state splitting at $8300cm-1$. As a result, the numbering of the $b¯1B1$ bending vibrational levels needs to be changed from $\nu 2$ to $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow><mrow\; data-mjx-texclass="ORD">-2</mrow>}$. Furthermore, abnormally strong $\Delta K2=3$ transitions in the $\bar{a} \leftarrow $b band and the tunneling effect in the high bending overtones will be discussed.