Rotationally resolved double resonance spectra of NO Rydberg states near the first ionization limit

Abstract

Optical–optical double resonance multiphoton ionization spectroscopy is used to study several Rydberg states of nitric oxide with the A(3sσ) 2Σ+, v=1 state as an intermediate level. These v=1 Rydberg states include the 8s, 9s, 7f, 8f, and 8p, but no d states are observed. The states are rotationally resolved due to the capability of optical–optical double resonance experiments to select particular rotational levels of the intermediate state. A rotationally analysis of the data for the 8s and 9s states yields values for the rotational constant, the centrifugal distortion constant, and the term energy of the lowest rotational level for each state. Analysis of the data for the 7f and 8f states yields values for the ion core quadrupole moment, polarizability and rotational constant, and a correction for core penetration. These constants are obtained by a generalized least-squares fit to a long-range interaction model for electrostatic forces between the ion core and the Rydberg electron. The 8p, v=1 state is perturbed, probably by an interaction with the 5f, v=2 state. One example of quantum interference between the 5f level with v=2, N=4, and ℒ=−3, and the 8p 2Σ+, v=1, N=4 level has been analyzed.