Further Resolution of Two Parallel Bands of Ammonia and the Interaction between Vibration and Rotation

The fundamental low frequency parallel band at $10\mu$ and its upper stage band at $16\mu$ have been re-examined under high dispersion. It is found that most of the fine structure lines hitherto reported as single are resolved into multiplets. The positions of the lines may be accounted for accurately by assuming that the energy levels have the form, $\frac{W^{s,a}}{\mathrm{hc}}=\frac{W_V^{}{}_{}{}^{s,a}}{\mathrm{hc}}+A_V^{}{}_{}{}^{s,a}(J^2+J-K^2)+C_V^{}{}_{}{}^{s,a}{K}^2+F\left(\mathrm{JK}\right).$ The superscripts $s$ or $a$ indicate whether the level in question is the lower or the upper of the two levels produced by the double minimum potential. $F\left(\mathrm{JK}\right)\mathrm{}$ is the small centrifugal distortion term calculated by Slawsky and Dennison. The constants $A_0^{}{}_{}{}^s$, $A_0^{}{}_{}{}^a$, $A_1^{}{}_{}{}^s$, $A_1^{}{}_{}{}^a$, $A_2^{}{}_{}{}^s$, $C_1^{}{}_{}{}^s-C_0^{}{}_{}{}^a$ and $C_1^{}{}_{}{}^a-C_0^{}{}_{}{}^s$ are determined from the experimental data. The following vibrational energies are also found, $W_1^{}{}_{}{}^s=932.24\mathrm{hc}$, $W_1^{}{}_{}{}^a=968.08\mathrm{hc}$ and $W_2^{}{}_{}{}^s=1597.4\mathrm{hc}$.