Knowledge Bank

The rotational spectrum of $H15NO3$ was recorded using isotope enriched samples at Ohio State University with the FASSST spectrometer and at the Jet Propulsion Laboratory with the cascaded frequency multiplication spectrometer. The OSU system used a heated cell over the frequency range of 118-370 GHz while the JPL room temperature measurements included the frequency ranges of 74-109, 400-410, 639-656, and 800-850 GHz. Transitions in the ground and six lowest vibrational states, $61$, $71$, $81$, $91$, and the $51/92$ dyad, have been assigned and fit using Watson-type Hamiltonians. The $91$ and $92$ states require torsional parameters to account for the observed torsional splitting of $\sim$2.4 MHz and $\sim$70 MHz, respectively. Fermi and Coriolis interactions were included to accurately describe the strong interactions in the $51/92$ dyad and to account for an observed torsional splitting of $\sim$15 MHz induced onto the $51$ state. The analysis of each state will be presented along with a discussion of the spectroscopic constants.