Fine structure of metastable 4He2 using zeeman-decelerated molecular-beam resonance spectroscopy

Semeria, Luca

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https://hdl.handle.net/2142/100576 Copy

Description

Title

Fine structure of metastable 4He2 using zeeman-decelerated molecular-beam resonance spectroscopy

Author(s)

Semeria, Luca

Contributor(s)

• Merkt, Frederic
• Schmutz, Hansjürg
• Agner, Josef A.
• Jansen, Paul

Issue Date

2018-06-21

Keyword(s)

Cold and ultracold molecules

Abstract

The a 3Σ + u state of 4He2 is a metastable state with a lifetime of about 18 s. The spin-spin and spin-rotation interactions result in a splitting of each rotational level N into three components J = N, N ± 1. The fine structure intervals of the N = 1, 3, 5, 7 − 11 and 25 - 29 have been measured by radio frequency (rf) spectroscopya b c d and were included in a global analysis of the a 3Σ + u state e . A new measurement of the fine structure of all rotational levels between N = 1 and 21 of the a 3Σ + u (v = 0) state will be presented. The J = N fine-structure components, which are high-field seeking in magnetic fields, have been eliminated using a multistage Zeeman decelerator, and repopulated from the low-field-seeking J = N ± 1 components using rf radiation prior to detection by excitation to Rydberg states followed by pulsed-field ionization. The low velocity of the Zeeman decelerated beamf g enabled long interaction times of the molecules with the rf radiation and therefore a reduction of the transit-time broadening down to 10 kHz (FWHM), allowing the transition frequencies to be determined very accurately. The fine structure has been analyzed using an effective Hamiltonian to obtain improved values of the spinspin and spin-rotation coupling constants for the a 3Σ + u (v = 0) metastable state of 4He2, including centrifugal distortion corrections.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/100576

DOI

10.15278/isms.2018.RG08

Copyright and License Information

Copyright 2018 Luca Semeria

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