Imaging Electronic Excitation of NO by Ultrafast Laser Tunneling Ionization

• Published in: Physical review letters Vol. 116; no. 16; p. 163002
• Main Authors: Endo, Tomoyuki, Matsuda, Akitaka, Fushitani, Mizuho, Yasuike, Tomokazu, Tolstikhin, Oleg I, Morishita, Toru, Hishikawa, Akiyoshi
• Format: Journal Article
• Language: English
• Published: United States 22.04.2016
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.116.163002

Tunneling-ionization imaging of photoexcitation of NO has been demonstrated by using few-cycle near-infrared intense laser pulses (8 fs, 800 nm, 1.1×10^{14}  W/cm^{2}). The ion image of N^{+} fragment ions produced by dissociative ionization of NO in the ground state, NO (X^{2}Π,2π)→NO^{+}+e^{-}→N^{+}+O+e^{-}, exhibits a characteristic momentum distribution peaked at 45° with respect to the laser polarization direction. On the other hand, a broad distribution centered at ∼0° appears when the A^{2}Σ^{+} (3sσ) excited state is prepared as the initial state by deep-UV photoexcitation. The observed angular distributions are in good agreement with the corresponding theoretical tunneling ionization yields, showing that the fragment anisotropy reflects changes of the highest-occupied molecular orbital by photoexcitation.