Nonlinear Pressure Shifts of Alkali-Metal Atoms in Inert Gases

Gong, Feiyan; Jau, Yuan‐Yu; Happer, W.

doi:10.1103/physrevlett.100.233002

Cited by 25 publications

(51 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These unique characteristics have made vdW complexes an attractive platform for the study of chemical reaction dynamics [12][13][14][15][16] and surface interactions 17 . They also play a key role in nonlinear optical phenomena and decoherence of dense atomic and molecular gases 18 . Once formed, the vdW molecules can decay via collision-induced dissociation 19 , chemical exchange 13,15,16 and electronic, vibrational, rotational, and Zeeman predissociation 17,20 .…”

mentioning

confidence: 99%

See 1 more Smart Citation

Formation and dynamics of van der Waals molecules in buffer-gas traps

Brahms

Tscherbul

Zhang

et al. 2011

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

We show that weakly bound He-containing van der Waals molecules can be produced and magnetically trapped in buffer-gas cooling experiments, and provide a general model for the formation and dynamics of these molecules. Our analysis shows that, at typical experimental parameters, thermodynamics favors the formation of van der Waals complexes composed of a helium atom bound to most open-shell atoms and molecules, and that complex formation occurs quickly enough to ensure chemical equilibrium. For molecular pairs composed of a He atom and an S-state atom, the molecular spin is stable during formation, dissociation, and collisions, and thus these molecules can be magnetically trapped. Collisional spin relaxations are too slow to affect trap lifetimes. However, 3 He-containing complexes can change spin due to adiabatic crossings between trapped and untrapped Zeeman states, mediated by the anisotropic hyperfine interaction, causing trap loss. We provide a detailed model for Ag 3 He molecules, using ab initio calculation of Ag-He interaction potentials and spin interactions, quantum scattering theory, and direct Monte Carlo simulations to describe formation and spin relaxation in this system. The calculated rate of spin-change agrees quantitatively with experimental observations, providing indirect evidence for molecular formation in buffer-gas-cooled magnetic traps.The ability to cool and trap molecules holds great promise for new discoveries in chemistry and physics [1][2][3][4] . Cooled and trapped molecules yield long interaction times, allowing for precision measurements of molecular structure and interactions, tests of fundamental physics 5,6 , and applications in quantum information science 7 . Chemistry shows fundamentally different behavior for cold molecules 8 , and can be highly controlled based on the kinetic energy, external fields 9 , and quantum states 10 of the reactants.Experiments with cold molecules have thus far involved two classes of molecules: Feshbach molecules and deeply bound ground-state molecules. Feshbach molecules are highly vibrationally excited molecules, bound near dissociation, which interact only weakly at long range, due to small dipole moments. They are created by binding pairs of ultracold atoms using laser light (photoassociation), ac magnetic fields (rf as- . By contrast, ground-state heteronuclear molecules often have substantial dipole moments and are immune to spontaneous decay and vibrational relaxation, making these molecules more promising for applications in quantum information processing 7 and quantum simulation 11 . These molecules are either cooled from high temperatures using techniques such as buffer-gas cooling or Stark deceleration, or are created via coherent deexcitation of Feshbach molecules.This article introduces a third family to the hierarchy of trappable molecules -van der Waals (vdW) complexes. VdW molecules are bound solely by long-range dispersion interactions, leading to the weakest binding energies of any groundstate molecules, on the order of a wavenum...

show abstract

mentioning

confidence: 99%

“…They were first observed in the spin relaxation of Rb due to the formation of RbAr and RbKr molecules 30 . Such molecules mediate efficient spin-exchange between alkali atoms and rare-gas nuclei 31 and have been shown to limit the precision of vapor-cell based atomic clocks 18 . Dense Rg vapors have also been used to spectroscopically observe MRg excimers 32 .…”

mentioning

confidence: 99%

Formation and dynamics of van der Waals molecules in buffer-gas traps

Brahms

Tscherbul

Zhang

et al. 2011

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…For this work, we extended our measurements to higher pressures than in Ref. [1]. We found that stabilization of the temperature gradient along the section of the vapor cell that exits the oven was necessary to reduce the additional clock noise and drift at higher pressures that are due to temperature-induced changes in the cell volume.…”

Section: Methodsmentioning

confidence: 93%

“…1 is a sketch of the experimental setup for both the Rb and Cs measurements, which is a laser-pumped, vapor-cell atomic clock that closely follows the description in Ref. [1]. To isolate the pressure shift, we suppress the frequency shift due to the laser, known as the light shift, by using feedback to lock the laser to a (pressure-dependent) zero-shift optical frequency that produces no light shift.…”

Section: Methodsmentioning

confidence: 99%

“…The frequency shift of these resonances due to the buffer gas is known as the pressure shift. The size of the shift depends on the temperature and is remarkably linear with the buffer gas pressure p. Previous work has uncovered a nonlinear dependence of the pressure shifts of 87 Rb and 133 Cs in Ar and Kr, but not He and N 2 , which is thought to be due to the loosely-bound van der Waals molecules that are known to form between alkali-metal and buffer-gas atoms in Ar, Kr, and Xe, but not He and N 2 [1], [2]. The precise measurement of nonlinear pressure shifts is a means to study van der Waals molecules and poorly-known interatomic potentials, and is important for determining optimal buffer gas mixtures.…”

Section: Introductionmentioning

confidence: 94%

See 1 more Smart Citation

Nonlinear pressure shifts of alkali-metal atoms in Xenon

McGuyer

Xia

Jau

et al. 2011

2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum (FCS) Proceedings

View full text Add to dashboard Cite

We demonstrate that the microwave resonant frequencies of ground-state 87 Rb and 133 Cs atoms have a nonlinear dependence on the pressure of the buffer gas Xe. Surprisingly, though the frequency shifts of Rb and Cs in the heavy noble gases Ar, Kr, and Xe are all negative, the nonlinearity in Xe is of the opposite sign to the nonlinearities in Ar and Kr. This discrepancy suggests that the frequency shifts due to alkali-noble van der Waals molecules in Xe are opposite in sign to the those in Ar and Kr. The nonlinearity in Xe shows a reproducible deviation from a simple model used to describe the shifts in Ar and Kr, which suggests that the spin-rotation interaction plays a significant role in the frequency shifts due to molecules. No nonlinearities were observed with the gases He and N2, as expected, and also Ne to within experimental error, which suggests that molecules do not form in Ne. Additionally, we present improved measurements of the shifts of Rb in Ar and Kr and of Rb and Cs in He and N2.

show abstract

References

2010

Optically Pumped Atoms

View full text Add to dashboard Cite

Nonlinear Pressure Shifts of Alkali-Metal Atoms in Inert Gases

Cited by 25 publications

References 9 publications

Formation and dynamics of van der Waals molecules in buffer-gas traps

Formation and dynamics of van der Waals molecules in buffer-gas traps

Nonlinear pressure shifts of alkali-metal atoms in Xenon

References

Contact Info

Product

Resources

About