Rotationally-resolved High-resolution Laser Spectroscopy Of The B 2e′← X 2a2′ Transition Of 15no3 Radical

Abstract

Nitrate radical (NO$_{3}$) has two electronic excited states: $A~^{2}E"$ and

$B~^{2}E'$ near the electronic ground state: $X~^{2}A_{2}'$. These three

electronic states can vibronically interact each other. Therefore, NO$_{3}$

is one of the great subjects for understanding intramolecular interactions in

polyatomic radicals. High-resolution fluorescence excitation spectrum and its

magnetic effect of the 662 nm band, which is assigned as the 0 - 0 band of the $B~^{2}E' \leftarrow X~^{2}A_{2}'$ transition, of $^{14}$NO$_{3}$ have been observed.\footnote{K. Tada, W. Kashihara, S. Kasahara, M. Baba, T. Ishiwata, and E. Hirota, The 68th OSU Symposium, WJ04 (2013).}

The observed $^{14}$NO$_{3}$ spectrum was too complicated to be analyzed

rotationally because of less rotational regularity. In this work, we observed

high-resolution fluorescence excitation spectrum of the 662 nm band of $^{15}$NO$_{3}$.

The observed region was 15080 - 15103 cm$^{-1}$. We also observed the Zeeman

splitting of intense rotational lines for unambiguous rotational assignment.

A part of the observed rotational lines was successfully assigned by using

ground state combination differences calculated from the reported molecular

constants\footnote{R. Fujimori, N. Shimizu, J. Tang, T. Ishiwata, and K. Kawaguchi, J. Mol. Spectrosc., 283, 10 (2013).}

and the observed Zeeman patterns. The effective molecular constants of the

excited state were determined under the oblate symmetric-top model.