THE ROTATIONAL SPECTRUM OF $H^{15}NO_{3}$: ALL STATES BELOW 1000 $cm^{-1}$

Abstract

Author Institution: Department of Physics, Wright State University, Dayton OH 45435; Department of Physics, University of South Alabama, Mobile, AL 36688; Department of Physics, The Ohio State University, Columbus, OH 43210; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099The rotational spectrum of $H^{15}NO_{3}$ 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, $6^{1}$, $7^{1}$, $8^{1}$, $9^{1}$, and the $5^{1}/9^{2}$ dyad, have been assigned and fit using Watson-type Hamiltonians. The $9^{1}$ and $9^{2}$ 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 $5^{1}/9^{2}$ dyad and to account for an observed torsional splitting of $\sim$15 MHz induced onto the $5^{1}$ state. The analysis of each state will be presented along with a discussion of the spectroscopic constants