Knowledge Bank

High-resolution Fourier transform infrared spectra of the NO$3$ $\nu 4$ bands of $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}$N and $\mathrm{<mrow\; data-mjx-texclass="ORD">15</mrow>}$N isotopic species were observed in the 365 and 360 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ region. Observed lines were used to determine $\Delta$K=3 combination differences of the ground state coupled with transition frequencies of the $\nu 3$ hot band $\nu 3$ + $\nu 4$ - $\nu 4$ in 1127 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ region \textbf{268}, 85 (2011).} and $\nu 3$ + $\nu 4$ band in 1492 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ region, which made it possible to determine the rotational C$0$ constants of 0.228 6321(67) cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ and 0.228 674(11) cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ for $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}$NO$3$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">15</mrow>}$NO$3$ , respectively. Inertial defects of several vibrational states were calculated by using a formula of Jagod and Oka \textbf{139}, 313 (1990).} and compared with the observed values. Although the observed Coriolis coupling constants $\zeta$$4$=-0.188 ($\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}$NO$3$ ) and -0.156 ($\mathrm{<mrow\; data-mjx-texclass="ORD">15</mrow>}$NO$3$ ) are largely different from the expected value of -0.7 from a force field calculation, observed inertial detects are in good agreement with calculated values, for example, $\Delta obs$(Gr.)= 0.206 [0.223] amu\AA$2$, (v$4$=1) 0.434[0.437] amu\AA$2$ etc, where calculated values are given in square brackets.