Spectra and dynamics of H2 near the second dissociation threshold: Tunneling and Feshbach resonance

Yuanyuan Han, Peng Wang, and Yuxiang Mo
Phys. Rev. A 106, 012824 – Published 29 July 2022
PDFHTMLExport Citation

Abstract

Both tunneling and Feshbach resonances occur near the second dissociation threshold of H2. There are three channels, H(1s)+H(2p1/2), H(1s)+H(2s1/2), and H(1s)+H(2p3/2), which correlate to the 2pσB1Σu+, 3pσB1Σu+, and 2pπC1Πu states, respectively. For the 2pπC state, there is a potential barrier near the dissociation limit, which accommodates bound states υ=13,J=2,3 with energies above the threshold. The tunneling dissociation results in H(1s)+H(2p3/2), while Feshbach resonances produce H(1s)+H(2s1/2) or H(1s)+H(2p1/2). We measured the rotationally resolved spectra and determined the corresponding spectroscopic parameters. To study the dissociation dynamics, the spin-orbit branching ratios, and the fragment anisotropy parameters along the line profiles have been measured by a combination of Rydberg state ionization, velocity map ion imaging, and delay-time-curve methods. For the predissociation of the 2pπC1Πu+(υ=13,J=2) state with fragment kinetic energy of 0.7cm1, only the fragment H(2p1/2) was observed. For the 2pπC1Πu(υ=13,J=3) state with fragment kinetic energy of 36cm1, the branching ratio between H(2p1/2) and H(2p3/2) was found to be close to the diabatic limit, and the predissociation should occur via tunneling and coupling with a triplet state near the dissociation limit. For the 2pπC1Πu+,υ=13,J=3 state, the predissociation should occur via tunneling, and coupling with the 3pσB1Σu+ and 2pσB1Σu+ states.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
6 More
  • Received 29 May 2022
  • Accepted 12 July 2022

DOI:https://doi.org/10.1103/PhysRevA.106.012824

©2022 American Physical Society

Physics Subject Headings (PhySH)

Atomic, Molecular & Optical

Authors & Affiliations

Yuanyuan Han, Peng Wang, and Yuxiang Mo*

  • Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China

  • *Correspondence: ymo@mail.tsinghua.edu.cn

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 106, Iss. 1 — July 2022

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review A

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×