HIGH RESOLUTION ROTATIONAL SPECTROSCOPY STUDY OF THE ZEEMAN EFFECT IN THE 2 Π 1/2 MOLECULE PbF Alex...

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HIGH RESOLUTION ROTATIONAL SPECTROSCOPY STUDY OF THE ZEEMAN EFFECT IN THE 2 Π 1/2 MOLECULE PbF Alex Baum , Benjamin Murphy, Richard Mawhorter Trevor J. Sears T. Zh.Yang, P.M Rupasinghe, C.P. McRaven, N.E. Shafer-Ray Lukas D. Alphei & Jens- Uwe Grabow Pomona College, Claremont, CA Brookhaven National Laboratory, Upton, NY University of Oklahoma, Norman, OK Leibniz Universität, Hannover, Germany June 23, 2011

Transcript of HIGH RESOLUTION ROTATIONAL SPECTROSCOPY STUDY OF THE ZEEMAN EFFECT IN THE 2 Π 1/2 MOLECULE PbF Alex...

Page 1: HIGH RESOLUTION ROTATIONAL SPECTROSCOPY STUDY OF THE ZEEMAN EFFECT IN THE 2 Π 1/2 MOLECULE PbF Alex Baum, Benjamin Murphy, Richard Mawhorter Trevor J.

HIGH RESOLUTION ROTATIONAL SPECTROSCOPY STUDY OF THE ZEEMAN EFFECT IN THE 2Π1/2 MOLECULE PbF

Alex Baum, Benjamin Murphy, Richard Mawhorter

Trevor J. Sears

T. Zh.Yang, P.M Rupasinghe, C.P. McRaven, N.E. Shafer-Ray

Lukas D. Alphei & Jens-Uwe Grabow

Pomona College, Claremont, CA

Brookhaven National Laboratory, Upton, NY

University of Oklahoma, Norman, OK

Leibniz Universität, Hannover, Germany

June 23, 2011

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Facts about PbF

1. 1 unpaired electron

2. 2Π1/2 ground state

3. 4 isotopes- 204Pb19F, 206Pb19F, 207Pb19F, 208Pb19F- 19F I = ½- (even)Pb I = 0- 207Pb I = ½

4. e-EDM sensitive

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Why do we like PbF?

•Very high internal electric field due to heavy nucleus

•Closely spaced states of opposite parity

•Small molecular g-factor (g≈0.05)

•Sensitivity to e-EDM in ground electronic state

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Experimental Setup

Supersonic-jet Fourier transform microwave spectrometer located at Leibniz Universität Hannover

- 2-26.5 GHz range- Accurate to within 0.5 kHz

Laser Ablation- 20Hz infrared laser pulses ablate

lead into ions- Ions combine with fluorine

introduced as ~1% SF6 in Ne buffer gas

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Experimental Setup

3 pairs of Helmholtz coils

Able to produce magnetic fields up to ~4 Gauss

From Jens-Uwe Grabow and Walther Caminati. Microwave spectroscopy: Experimental techniques. Frontiers of Molecular Spectroscopy, page p. 383. Elsevier, 2009

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Zeeman Effect

2J+1 degeneracy of the spatial components of the rotational state with total angular momentum quantum number J lifted under application of a magnetic field

•Magnitude of splitting proportional to strength of magnetic field

•Selection rule ΔMJ = 0 or +/-1 depending on relative orientation of applied magnetic field to MW electric field

J

J

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Example Zeeman Spectra

Perpendicular Magnetic Field: ∆M = ± 1

Parallel Magnetic Field: ∆M = 0

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Parallel Magnetic Field: ∆M = 0

F = 3/2 → F = 5/2 transition: 207PbF22541.912MHz

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Perpendicular Magnetic Field: ∆M = ± 1

F = 3/2 → F = 5/2 transition: 207PbF22541.912MHz

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g-factor Definition

In general, the g-factor relates the magnetic moment of a particle to its associated angular momentum.

Examples include:

•Electron spin g-factor μS=geμBS/ħ where μB is the Bohr magneton.

•Nuclear g-factor• μN=gNμNI/ħ where μN is the nuclear magneton.

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Zeeman Effect in 208Pb19F

Can approximate θ = 0 and μN/μB m∝ e/mp ≈ 1/1800 ≈ 0 with about 95% accuracy...

Goal: Determine G|| and G⊥

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Zeeman Effect in 208Pb19F

With this approximation

Now, for an individual quantum state i

Page 13: HIGH RESOLUTION ROTATIONAL SPECTROSCOPY STUDY OF THE ZEEMAN EFFECT IN THE 2 Π 1/2 MOLECULE PbF Alex Baum, Benjamin Murphy, Richard Mawhorter Trevor J.
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Conclusions

[2] K. I. Baklanov, A. N. Petrov, A. V. Titov, and M. G. Kozlov. Towards the electron EDM search. Theoretical study of PbF. ArXiv e-prints, January 2010.[19] M G Kozlov, V I Fomichev, Y Y Dmitriev, L N Labzovsky, and A V Titov. Calculation of the P- and T-odd spin-rotational hamiltonian of the PbF molecule. Journal of Physics B: Atomic and Molecular Physics, 20(19):4939, 1987.[25] P.M. Rupasinghe. Private Communication, 2010.

•This is the first experimental determination of the sign, and increases the precision in our knowledge of the value of the body fixed g-factors for PbF by more than an order of magnitude.

•This knowledge provides a strong foundation for the design of a robust and finely-tuned e-EDM experiment using PbF.

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Acknowledgements

Special thanks to

•Dr. Richard Mawhorter•Dr. Jens-Uwe Grabow•Dr. Neil Shafer-Ray

Funded by a Sontag Fellowship from Pomona College