The European Physical Journal Special Topics

, Volume 163, Issue 1, pp 55–69 | Cite as

Prospects for precision measurements on ammonia molecules in a fountain

  • H. L. Bethlem
  • M. Kajita
  • B. Sartakov
  • G. Meijer
  • W. Ubachs
Open Access


The recent demonstration of cooling and manipulation techniques for molecules offer newpossibilities for precision measurements in molecules. Here, we present the design of a molecularfountain based on a Stark decelerated molecular beam. In this fountain, ammonia molecules aredecelerated to a few meter per second, cooled to sub microKelvin temperatures and subsequentlylaunched. The molecules fly upwards some 30 cm before falling back under gravity, thereby passing amicrowave cavity twice – as they fly up and as they fall back down. The effective interrogationtime in such a Ramsey type measurement scheme includes the entire flight time between the twotraversals through the driving field, which is on the order of a 1/2 second. We present numericalsimulations of the trajectories through the decelerator and estimate the expected count rate. Wepresent an evaluation of the expected stability and accuracy for the inversion transition in15NH3 around 22.6 GHz. The estimated frequency instability is \(7\times10^{-12}~\tau^{-1/2}\), with τ being the measurement time in seconds. With a careful design ofthe interogation zone, systematic frequency shifts are kept below 10-14. Besides serving as aproof-of-principle, these measurements may be used as a test of the time-variation of fundamentalconstants using the sensitivity of the tunneling motion to a change of the proton-electron massratio.


  1. S. Bize, et al., J. Phys. B. – Atom. Mol. Opt. Phys. 38, S449 (2005)Google Scholar
  2. T.P. Heavner, et al., Metrologia 42, 411 (2005)Google Scholar
  3. M.M. Boyd, et al., Phys. Rev. Lett. 98, 083002 (2007)Google Scholar
  4. W.H. Oskay, et al., Phys. Rev. Lett. 97, 020801 (2006)Google Scholar
  5. H.L. Bethlem, G. Meijer, Int. Rev. Phys. Chem. 22, 73 (2003)Google Scholar
  6. J. Doyle, B. Friedrich, R.V. Krems, F. Masnou-Seeuws, Eur. Phys. J. D 31, 149 (2004)Google Scholar
  7. J. van Veldhoven, J. Küpper, H.L. Bethlem, B. Sartakov, A.J. van Roij, G. Meijer, Eur. Phys. J. D 31, 337 (2004)Google Scholar
  8. E.R. Hudson, H.J. Lewandowski, B.C. Sawyer, J. Ye, Phys. Rev. Lett. 96, 143004 (2006)Google Scholar
  9. J.J. Hudson, B.E. Sauer, M.R. Tarbutt, E.A. Hinds, Phys. Rev. Lett. 89, 023003 (2002)Google Scholar
  10. D. Kawall, F. Bay, S. Bickman, Y. Jiang, D. DeMille, Phys. Rev. Lett. 92, 133007 (2004)Google Scholar
  11. D. DeMille, S.B. Cahn, D. Murphree, D.A. Rahmlow, M.G. Kozlov, Phys. Rev. Lett. 100, 023003 (2008)Google Scholar
  12. Ch. Daussy, et al., Phys. Rev. Lett. 83, 1554 (1999)Google Scholar
  13. A. Shelkovnikov, R.J. Butcher, C. Chardonnet, A. Amy-Klein, Phys. Rev. Lett. 100, 150801 (2008)Google Scholar
  14. V.V. Flambaum, Eur. Phys. J. Special Topics 163, 159 (2008)Google Scholar
  15. P. Foreman, Proc. IEEE 73, 1181 (1985)Google Scholar
  16. J.P. Gordon, H.J. Zeiger, C.H. Townes, Phys. Rev. 99, 1264 (1955)Google Scholar
  17. S.G. Kukolich, Phys. Rev. 156, 83 (1967)Google Scholar
  18. J.T. Hougen, J. Chem. Phys. 156, 83 (1972)Google Scholar
  19. J. van Veldhoven, R.T. Jongma, B. Sartakov, W.A. Bongers, G. Meijer, Phys. Rev. A 66, 032501 (2002)Google Scholar
  20. S. Urban, J. Quant. Spec. Rad. Trans. 48, 675 (1992)Google Scholar
  21. C.H. Townes, A.L. Schawlow, Microwave Spectroscopy (McGraw-Hill, New York, 1955)Google Scholar
  22. H.L. Bethlem, F.M.H. Crompvoets, R.T. Jongma, S.Y.T. van de Meerakker, G. Meijer, Phys. Rev. A 65, 053416 (2002)Google Scholar
  23. F.M.H. Crompvoets, R.T. Jongma, H.L. Bethlem, G. Meijer, Phys. Rev. Lett. 89, 093004 (2002)Google Scholar
  24. M.N.R. Ashfold, R.N. Dixon, N. Little, R.J. Stickland, C.M. Western, J. Chem. Phys. 89, 1754 (1988)Google Scholar
  25. J. Vanier, C. Audoin, The Quantum Physics of Atomic Frequency Standard (IOP Publishing, Bristol, 1989)Google Scholar
  26. M. Kajita, Phys. Rev. A 74, 032710 (2006)Google Scholar
  27. W.M. Itano, L.L. Lewis, D.J. Wineland, Phys. Rev. A 25, 1233 (1982)Google Scholar
  28. S. Hoekstra, et al., Phys. Rev. Lett. 98, 133001 (2007)Google Scholar
  29. N. Vanhaecke, O. Dulieu, Mol. Phys. 105, 1723 (2007)Google Scholar
  30. S. Urban, D. Papousek, V.M. Devi, B. Fridovich, R. D’Cunha, K.N. Rao, J. Mol. Spectrosc. 86, 38 (1984)Google Scholar
  31. S.R. Jefferts, R.E. Drullinger, A. DeMarchi, Proc. IEEE Int. Freq. Control Symp. (1998)Google Scholar
  32. J.K. Webb, et al., Phys. Rev. Lett. 87, 091301 (2001)Google Scholar
  33. E. Reinhold, R. Buning, U. Hollenstein, A. Ivanchik, P. Petitjean, W. Ubachs, Phys. Rev. Lett. 96, 151101 (2006)Google Scholar
  34. E. Peik, S. Karshenboim, Eur. Phys. J. Special Topics 163, 1 (2008)Google Scholar
  35. X. Calmet, H. Fritzsch, Eur. Phys. J. C 24, 693 (2002)Google Scholar
  36. J.-P. Uzan, Rev. Mod. Phys. 75, 403 (2003)Google Scholar
  37. P. Helminger, F.C. DeLucia, W. Gordy, H.W. Morgan, P.A. Staats, Phys. Rev. A 9, 12 (1974)Google Scholar

Copyright information

© EDP Sciences and Springer 2008

Authors and Affiliations

  • H. L. Bethlem
    • 1
    • 2
  • M. Kajita
    • 3
  • B. Sartakov
    • 4
  • G. Meijer
    • 2
  • W. Ubachs
    • 1
  1. 1.Laser Centre Vrije UniversiteitAmsterdamThe Netherlands
  2. 2.Fritz-Haber-Institut der Max-Planck-GesellschaftBerlinGermany
  3. 3.National Institute of Information and Communications TechnologyTokyoJapan
  4. 4.General Physics Institute RASMoscowRussia

Personalised recommendations