Single and sequential double ionization of NO radical in intense laser fields

Shinichi Fukahori; Atsushi Iwasaki; Kaoru Yamanouchi; Hirokazu Hasegawa

doi:10.1063/5.0077239

Single and sequential double ionization of NO radical in intense laser fields

J Chem Phys. 2022 Mar 7;156(9):094307. doi: 10.1063/5.0077239.

Authors

Shinichi Fukahori¹, Atsushi Iwasaki², Kaoru Yamanouchi², Hirokazu Hasegawa¹

Affiliations

¹ Department of Integrated Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
² Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

PMID: 35259906
DOI: 10.1063/5.0077239

Abstract

We examine the dependences of the single and double ionization probabilities of NO radical on the angle between the NO axis and the laser polarization direction in an intense laser field (790 nm, 100 fs, 1-10 × 10¹⁴ W/cm²) and show that the double ionization is enhanced when the NO axis is parallel to the laser polarization direction. We reveal that the angular dependence of the sequential double ionization probability is determined by the shape of the 5σ orbital of NO⁺ from which the second photoelectron is emitted in the ionization from NO⁺ to NO²⁺. We also reveal that the fast oscillation in the probability of the tunnel ionization of NO originating from a coherent superposition of the two spin-orbit components in the electronic ground X²Π state is described well based on the molecular Ammosov-Delone-Krainov (MO-ADK) theory in which the time evolution of the electron density distribution of the 2π orbital is taken into account.