This talk will present several exciting nuggets from the last half-century of progress in our understanding of Rydberg electron physics in atoms and small molecules. Some key elements of this deepened understanding have emerged from experiments that were understood through the multichannel quantum defect theory developed by Seaton, Fano, Jungen and their collaborators. That powerful combination has enabled spectra of remarkable complexity and richness to be quantitatively understood and qualitatively interpreted using this framework. Another aspect of Rydberg physics connects with Enrico Fermi’s treatment of the interaction between a slow electron and a distant ground state atom, which has been predicted to generate a new chemical bonding mechanism that can bind an exotic long range diatomic or triatomic molecule whose internuclear distances can be as large as a small virus. The production of this class of exotic, weakly-bound Rydberg molecules has been demonstrated in a remarkable series of experiments in the last few years.This talk will present several exciting nuggets from the last half-century of progress in our understanding of Rydberg electron physics in atoms and small molecules. Some key elements of this deepened understanding have emerged from experiments that were understood through the multichannel quantum defect theory developed by Seaton, Fano, Jungen and their collaborators. That powerful combination has enabled spectra of remarkable complexity and richness to be quantitatively understood and qualitatively interpreted using this framework. Another aspect of Rydberg physics connects with Enrico Fermi’s treatment of the interaction between a slow electron and a distant ground state atom, which has been predicted to generate a new chemical bonding mechanism that can bind an exotic long range diatomic or triatomic molecule whose internuclear distances can be as large as a small virus. The production of this class of exotic, weakly-bound Rydberg molecules has been demonstrated in a remarkable series of experiments in the last few years.

Frontiers in OpticsJan 1, 20130 citations

Accurate Determination of the Scattering Length of Metastable Helium Atoms Using Dark Resonances between Atoms and Exotic Molecules

Steven Moal, M. Portier, J. Kim +4 more

We present a new measurement of the $s$ -wave scattering length $a$ of spin-polarized helium atoms in the $2\text{ }^{3}S_{1}$ metastable state. Using two-photon photoassociation spectroscopy and dark resonances, we measure the energy ${E}_{v=14}=\ensuremath{-}91.35\ifmmode\pm\else\textpm\fi{}0.06\text{ }\text{ }\mathrm{MHz}$ of the least-bound state $v=14$ in the interaction potential of the two atoms. We deduce a value of $a=7.512\ifmmode\pm\else\textpm\fi{}0.005\text{ }\text{ }\mathrm{nm}$, which is at least 100 times more precise than the best previous determinations and is in disagreement with some of them. This experiment also demonstrates the possibility to create exotic molecules binding two metastable atoms with a lifetime of the order of $1\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$.We present a new measurement of the $s$-wave scattering length $a$ of spin-polarized helium atoms in the $2\text{ }^{3}S_{1}$ metastable state. Using two-photon photoassociation spectroscopy and dark resonances, we measure the energy ${E}_{v=14}=\ensuremath{-}91.35\ifmmode\pm\else\textpm\fi{}0.06\text{ }\text{ }\mathrm{MHz}$ of the least-bound state $v=14$ in the interaction potential of the two atoms. We deduce a value of $a=7.512\ifmmode\pm\else\textpm\fi{}0.005\text{ }\text{ }\mathrm{nm}$, which is at least 100 times more precise than the best previous determinations and is in disagreement with some of them. This experiment also demonstrates the possibility to create exotic molecules binding two metastable atoms with a lifetime of the order of $1\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$.

arXiv:cond-mat/0509286Physical Review LettersJan 20, 200692 citations

We present a new measurement of the

s

-wave scattering length

a

of spin-polarized helium atoms in the

2\text{ }^{3}S_{1}

metastable state. Using two-photon photoassociation spectroscopy and dark resonances, we measure the energy ${E}_{v=14}=\ensuremath{-}91.35\ifmmode\pm\else\textpm\fi{}0.06\text{ }\text{ }\mathrm{MHz}$ of the least-bound state

v=14

in the interaction potential of the two atoms. We deduce a value of $a=7.512\ifmmode\pm\else\textpm\fi{}0.005\text{ }\text{ }\mathrm{nm}$, which is at least 100 times more precise than the best previous determinations and is in disagreement with some of them. This experiment also demonstrates the possibility to create exotic molecules binding two metastable atoms with a lifetime of the order of $1\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$.