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Prof. Frederic Merkt

Laboratorium für Physikalische Chemie, ETH Zürich

Friday, January 24th, 2014 at 11:00:00 AM

Conference room Querzoli - LENS - via Nello Carrara 1 - Sesto Fiorentino (Florence)

Enrico Fermi Colloquium

Published on-line at 02:46:04 PM on Monday, January 20th, 2014

Rydberg atoms and molecules: from atom and molecule optics to precision spectroscopy

Rydberg states are electronically excited states, the spectral position of which can be described by Rydberg’s well-known formula [1]. The physical properties

Rydberg states are electronically excited states, the spectral position of which can be described by Rydberg’s well-known formula [1]. The physical properties of these states become very unusual at high values of the principal quantum number n [2]:Their polarizability scales as n7, the van der Waals interaction between two Rydberg atoms or molecules as n11, the maximal electric dipole that can be induced by an electric field as n2, the threshold field for field ionization as n-4, the spacing between adjacent states of a given Rydberg series as n-3, the absorption cross section from the ground state as n-3, the transition moment between neighboring Rydberg states as n2, their lifetime as n3, etc. These physical properties and their rapid variation with n form the basis of a growing number of applications of Rydberg states in chemistry and physics. The talk will begin with an overview of the properties of Rydberg states and their applications in physics and chemistry. I shall then present two specific applications of Rydberg states my group is interested in. In the first, we exploit the large dipole moments of Rydberg states to control the translational motion of atoms and molecules, and develop methods to accelerate, focus, deviate and reflect beams of atoms and molecules, the latest experiments being carried out near the surface of chips [3,4]. In the second, we use Rydberg states to carry out precision measurements of dissociation and ionization energies of molecules to test quantum electrodynamics calculations in small molecular systems such as H2 and He2 [5].

[1] J. R. Rydberg, Z. Phys. Chem. 5, 227 (1890)

[2] T. F. Gallagher, Rydberg Atoms (Cambridge University Press, Cambridge 1994)

[3] S. D. Hogan, P. Allmendinger, H. Saßmannshausen, H. Schmutz and F. Merkt, Phys. Rev. Lett. 108, Art. No. 063008:1–5 (2012)

[4] S. D. Hogan, J. A. Agner, F. Merkt, T. Thiele, S. Filipp and A. Wallraff, Phys. Rev. Lett. 108, Art. No. 063004:1–5 (2012)

[5] D. Sprecher, Ch. Jungen ,W. Ubachs and F. Merkt, Faraday Disc. 150, 51 (2011)

 

For further informations, please contact Prof. Diederik Wiersma.