University of Illinois Urbana-Champaign

Improvement of the dissociation energy of the hydrogen molecule (Part two)

Hoelsch, Nicolas

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1187612.pdf
3236.pdf

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https://hdl.handle.net/2142/100634

Description

Title
Improvement of the dissociation energy of the hydrogen molecule (Part two)
Author(s)
Hoelsch, Nicolas
Contributor(s)
  • Jungen, Christian
  • Ubachs, Wim
  • Salumbides, Edcel John
  • Eikema, K.S.E.
  • Bethlem, Hendrick
  • Niu, Ming Li
  • Hussels, Joël
  • Cheng, Cunfeng
  • Merkt, Frederic
  • Agner, Josef A.
  • Beyer, Maximilian
Issue Date
2018-06-22
Keyword(s)
Comparing theory and experiment
Date of Ingest
  • 2018-08-17T16:09:23Z
  • 2018-12-12T22:38:56Z
Abstract
The dissociation energy D0 of ortho H2 is a benchmark quantity in quantum chemistry, with recent QED calculations now approaching accuracies achievable in simple atoms. In the light of recent discrepancies between experiment and theory [1], a combined effort (see also part one) has been undertaken to provide an improved experimental value for D0. We report the transition frequency from the GK 1Σ + g (v = 1, N = 1) state to the 56p (N = 1, S = 0, F = 0 − 2) Rydberg state belonging to the series converging on the X+ 2Σ + g (v + = 0, N + = 1) ground state of ortho H+ 2 . A resonant three-photon excitation scheme was employed, using pulsed VUV and VIS laser sources to reach the intermediate GK state and a continuous-wave near-infrared (NIR) laser source for the transition to the Rydberg state. To reach the desired accuracy, the procedure involved [2]: (i) minimizing the Doppler width through the use of a doubly skimmed, supersonic molecular beam produced by a cryogenic pulsed valve, (ii) minimizing stray electric and magnetic fields, (iii) cancelling the first-order Doppler shift using two counterpropagating laser beams, (iv) calibrating the NIR-laser frequency using a frequency comb referenced to an atomic clock. The ionization energy of the intermediate GK state was obtained by adding the binding energy of the Rydberg state determined previously by millimeter-wave spectroscopy and multichannel quantum-defect theory [3]. In combination with the GK 1Σ + g (v = 1, N = 1) ← X 1Σ + g (v = 0, N = 1) transition frequency presented in part one, an order-of magnitude improvement for D0 at the 10−9 level of accuracy has been achieved, while remaining consistent with the previously most precise determination [4]. [1] M. Puchalski et al., Phys. Rev. A 95, 052506 (2017) [2] M. Beyer et al., Phys. Rev. A 97, 012501 (2018) [3] D. Sprecher et al., J. Chem. Phys. 140, 104303:1-18 (2014) [4] J. Liu et al., J. Chem. Phys. 130 (17), 174306 (2009)
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
eng
Permalink
http://hdl.handle.net/2142/100634
DOI
10.15278/isms.2018.FC07
Copyright and License Information
Copyright 2018 Nicolas Hoelsch

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Abstracts & Presentations - 2018 International Symposium on Molecular Spectroscopy PRIMARY