BEND-STRETCH FERMI RESONANCE IN $NO^{+}_{2}$ AS DETECTED IN THE CORE OF THE $3P\sigma$ RYDBERG STATE OF $NO_{2}$

Abstract

Rotational structure is assigned for the $(000), (010), (02^{0}0), (02^{2}0), (100), (03^{1}0)$ and $(03^{3}0)$ vibrational levels of the $3p\sigma$ Rydberg state of $NO_{2}$ by ionization-detected two-photon and double resonance electronic spectroscopy in transitions from the $^{2}A_{1}$ ground state. Accurate positions established for these fundamentals determine the vibrational constants $\omega_{2}$, $X_{22}$ and $g_{22}$, and characterize the Fermi resonance that couples $(02^{0}0)$ with (100) in the $NO^{+}_{2}$ cation core. Results are compared with isoelectronic $CO_{2}$.