Note The millimeter and submillimeter spectra of the ground state and excited m 9 , m 8 , m 7 , and m 6 vibrational states of HNO 3 Douglas T. Petkie, a Paul Helminger, b Rebecca A.H. Butler, c Sieghard Albert, d and Frank C. De Lucia c, * a Department of Physics, Wright State University, Dayton, OH 45435, USA b Department of Physics, University of South Alabama, Mobile, AL 36688, USA c Department of Physics, The Ohio State University, 174 West 18th Avenue, Columbus, OH 43210-1106, USA d Physical Chemistry, ETH Zurich, CH-8093, Switzerland Received 4 June 2002; in revised form 9 September 2002 The purpose of this note is to report in the literature the latest millimeter and submillimeter spectroscopic measurements and analyses for the rotational structure of a number of vibrational states of HNO 3 . Subsets of these data (and more commonly spectroscopic con- stants, energy levels, etc. derived from them) are widely used, often in multi-step, weighted analyses with infra- red data [1–14]. However, these multi-step processes do not make optimal use of the data and have the potential to significantly affect the calculation of spectroscopic constants and especially the uncertainties in these con- stants and synthetic spectra calculated from them [15,16]. For example, in the specific case of ThO, Al- britton et al. [15] show examples of both overestimates and under estimates by factors of 5–10 in the uncer- tainties of derived parameters that result from such a multi-step process. In this paper we report new analyses of these states and deposit in electronic form all of the original spectral data upon which they are based. This will make possible the direct inclusion of the data in mixed analyses, thereby maximizing the usefulness of their information content. We have published analyses of the rotational struc- tures of the ground state, m 9 , m 8 , m 7 , and m 6 [17–22]. During the course of subsequent work, we have accu- mulated significant additional data and have continually updated these analyses. In various forms these data have been incorporated in many analyses. For example, in most infrared analyses of rovibrational spectra, micro- wave data have been used to largely determine the ground state, often in conjunction with infrared com- bination differences in a weighted fit [3,4,6–8,13]. The inclusion of the very accurate microwave data in this reduction has been especially valuable because, without it, the many sums and differences (which are imposed by the DJ ¼ 0, 1 selection rule) necessary to calculate the energy of a high J line would result in significant accumulated error and a need to carefully consider the impact of this error in subsequent pro- cessing steps. Not only would this accumulated error make comparisons among different sets of energy levels difficult, it also would require rather detailed statistical procedures to make, for example, the uncertainties in calculated spectroscopic constants meaningful. How- ever, with the microwave data largely defining the ground state and the error in the absolute energy of upper state levels coming mostly from individual infra- red line measurements, the statistical problems associ- ated with the inability to access the original data are largely transcended. However, in many states there have been enough microwave data available to make significant contribu- tions to the definitions the rotational structure of the upper state as well. These include analyses of m 6 , m 7 , m 8 , and m 9 [1,11,23,24] the m 5 =2m 9 dyad [5,9], and m 8 þ m 9 [12,14]. Since these data are comparable in accuracy to the ground state data, it is statistically important that all of the data be available for direct inclusion in the analysis. Additionally, the processed data (e.g., energy levels) often reflects the interests of the authors. For example, the torsional motion associated with the m 9 mode Journal of Molecular Spectroscopy 218 (2003) 127–130 www.elsevier.com/locate/jms * Corresponding author. Fax: 1-614-292-7557. E-mail address: fcd@mps.ohio-state.edu (F.C. De Lucia). 0022-2852/03/$ - see front matter Ó 2003 Elsevier Science (USA). All rights reserved. doi:10.1016/S0022-2852(02)00025-5