Physical Review Letters

Doubly excited Rydberg states of the Na2 molecule

Christian Bordas, Jean Vialle, Michel Broyer

Published Mar 12, 1990• 6 citations

Abstract

We report here the first observation of ${\mathrm{Na}}_{2}$ Rydberg states with an excited ${\mathrm{Na}}_{2}^{+}$ 1 $^{2}\mathrm{\ensuremath{\Pi}}_{\mathit{u}}$ The principle of our experiment is to prepare a Rydberg state associated with the ion in its ground state and then to excite the ${\mathrm{Na}}_{2}^{+}$ core with a tunable laser. The autoionization processes occurring in these states as well as the internal energy redistribution of the singly excited Rydberg states are discussed. Finally, the energy levels of the 1 $^{2}\mathrm{\ensuremath{\Pi}}_{\mathrm{u}}$ state of ${\mathrm{Na}}_{2}^{+}$ are deduced.

DOI: 10.1103/physrevlett.64.1223

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Physical Review Letters

Doubly excited Rydberg states of the Na2 molecule

Christian Bordas, Jean Vialle, Michel Broyer

Published Mar 12, 1990• 6 citations

Publisher

Abstract

We report here the first observation of

{\mathrm{Na}}_{2}

Rydberg states with an excited

{\mathrm{Na}}_{2}^{+}

^{2}\mathrm{\ensuremath{\Pi}}_{\mathit{u}}

The principle of our experiment is to prepare a Rydberg state associated with the ion in its ground state and then to excite the

{\mathrm{Na}}_{2}^{+}

core with a tunable laser. The autoionization processes occurring in these states as well as the internal energy redistribution of the singly excited Rydberg states are discussed. Finally, the energy levels of the 1

^{2}\mathrm{\ensuremath{\Pi}}_{\mathrm{u}}

state of

{\mathrm{Na}}_{2}^{+}

are deduced.

DOI: 10.1103/physrevlett.64.1223

Related papers

Spectroscopy of autoionizing doubly excited states in ultracold Na2 molecules produced by photoassociation

Arjen Amelink, K. M. Jones, Paul D. Lett +2 more

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William E. Cooke, Thomas F. Gallagher, S. A. Edelstein +1 more

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The one- and two-colour spectra of Neon Rydberg states have been recorded in the energy region below the first ionization threshold. Access to this region is achieved by recording the yield of Ne2+ ions formed in an associative ionization process between atoms in the Rydberg states formed in the photonic excitation and ground state neutral atoms. The one-colour spectra permit a study of the AI process as a function of the principal quantum number of the photo-excited Rydberg state while the two-colour spectra give access to Rydberg series previously unobserved using photon excitation.The one- and two-colour spectra of Neon Rydberg states have been recorded in the energy region below the first ionization threshold. Access to this region is achieved by recording the yield of Ne2+ ions formed in an associative ionization process between atoms in the Rydberg states formed in the photonic excitation and ground state neutral atoms. The one-colour spectra permit a study of the AI process as a function of the principal quantum number of the photo-excited Rydberg state while the two-colour spectra give access to Rydberg series previously unobserved using photon excitation.

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Spectroscopic studies of the quantum defects for high-n singlet strontium Rydberg states

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Rydberg atoms have a long history of scientific research, but they have recently seen a resurgence in popularity due to their advantages when dealing with coupled internal Rydberg states, or externally-coupled Rydberg atoms. The use of convenient RF and/or microwave generation techniques allows for straightforward coupling of many nearby Rydberg states, enabling quantum simulation studies, such as the generation of a synthetic lattice. Strontium is particularly attractive for Rydberg atom studies due to its optically active core, which allows for two-electron excited states and its conveniently accessible transition frequencies that match those available using commercial diode lasers. Before these experiments and applications can be realized however, precise knowledge of Rydberg state energies and quantum defects is required. Therefore, this work undertakes an extensive study of the quantum defects of both singly and doubly-excited strontium Rydberg atoms for a wide range of n and l. Precision microwave spectroscopy between nearby Rydberg states produces an improved self-consistent set of quantum defects for singly-excited 1S0, 1P1, 1D2, and 1F3 states, described by their corresponding Rydberg-Ritz parameters. Quantum defects and lifetimes for autoionizing two-electron-states are also presented. These elucidate the effects of core penetration by the “outer” excited Rydberg electron on transitions within the core ion and on the Rydberg level itself.Rydberg atoms have a long history of scientific research, but they have recently seen a resurgence in popularity due to their advantages when dealing with coupled internal Rydberg states, or externally-coupled Rydberg atoms. The use of convenient RF and/or microwave generation techniques allows for straightforward coupling of many nearby Rydberg states, enabling quantum simulation studies, such as the generation of a synthetic lattice. Strontium is particularly attractive for Rydberg atom studies due to its optically active core, which allows for two-electron excited states and its conveniently accessible transition frequencies that match those available using commercial diode lasers. Before these experiments and applications can be realized however, precise knowledge of Rydberg state energies and quantum defects is required. Therefore, this work undertakes an extensive study of the quantum defects of both singly and doubly-excited strontium Rydberg atoms for a wide range of n and l. Precision microwave spectroscopy between nearby Rydberg states produces an improved self-consistent set of quantum defects for singly-excited 1S0, 1P1, 1D2, and 1F3 states, described by their corresponding Rydberg-Ritz parameters. Quantum defects and lifetimes for autoionizing two-electron-states are also presented. These elucidate the effects of core penetration by the “outer” excited Rydberg electron on transitions within the core ion and on the Rydberg level itself.

Nov 30, 20230 citations

TOWARD THE USE OF RYDBERG STATES FOR STATE-SELECTIVE PRODUCTION OF MOLECULAR IONS

David Grimes, Robert W. Field, Stephen L. Coy +1 more

The usual simplified view of Rydberg states of molecules as consisting of a single Rydberg electron loosely bound to a molecular ion core in a well-defined rotation-vibration state suggests an attractive possibility for state-selective production of molecular ions. A Rydberg electron excited above the energy of the ground state of the ion core will spontaneously autoionize, leaving behind a molecular ion. The autoionizing states are of strongly mixed character due to the ubiquitous nonadiabatic interactions between Rydberg series associated with different states of the ion core. Using our complete Multichannel Quantum Defect Theory (MQDT) fit model for CaF, we have predicted the locations and strengths of special autoionizing resonances that decay into a single rotation-vibration state of a molecular ion. Few molecules are as well characterized as CaF, nor as elegantly simple. We additionally describe the use of core nonpenetrating states as a general method to produce an ensemble of molecular ions in a single, selectable quantum state.The usual simplified view of Rydberg states of molecules as consisting of a single Rydberg electron loosely bound to a molecular ion core in a well-defined rotation-vibration state suggests an attractive possibility for state-selective production of molecular ions. A Rydberg electron excited above the energy of the ground state of the ion core will spontaneously autoionize, leaving behind a molecular ion. The autoionizing states are of strongly mixed character due to the ubiquitous nonadiabatic interactions between Rydberg series associated with different states of the ion core. Using our complete Multichannel Quantum Defect Theory (MQDT) fit model for CaF, we have predicted the locations and strengths of special autoionizing resonances that decay into a single rotation-vibration state of a molecular ion. Few molecules are as well characterized as CaF, nor as elegantly simple. We additionally describe the use of core nonpenetrating states as a general method to produce an ensemble of molecular ions in a single, selectable quantum state.

International Symposium on Molecular Spectroscopy (ISMS)Jun 19, 20140 citations

We report here the first observation of

{\mathrm{Na}}_{2}

Rydberg states with an excited

{\mathrm{Na}}_{2}^{+}

^{2}\mathrm{\ensuremath{\Pi}}_{\mathit{u}}

The principle of our experiment is to prepare a Rydberg state associated with the ion in its ground state and then to excite the

{\mathrm{Na}}_{2}^{+}

^{2}\mathrm{\ensuremath{\Pi}}_{\mathrm{u}}

state of

{\mathrm{Na}}_{2}^{+}

are deduced.

We have performed photoassociation spectroscopy to study the doubly excited states of

{\mathrm{Na}}_{2}

involved in the associative ionization of colliding

\mathrm{Na}(3P)

atoms. Rovibrational levels of two doubly excited potentials connected to the

{P}_{3/2}{+P}_{3/2}

asymptote, one of ${0}_{u}^{\ensuremath{-}}$ and one of

{1}_{u}

symmetry, have been identified. These two doubly excited potentials dominate the route to ionization used in photoassociation experiments of cold Na. Binding energies and rotational constants for all the vibrational levels with binding energies

<50\mathrm{GHz}

have been measured. The asymptotic potentials and short-range ionization probabilities are extracted from the data.

We report the observation of doubly excited autoionizing Rydberg states of Sr, belonging to the configuration

5{p}_{\frac{1}{2}}

\mathrm{nl}

. Our procedure involves a three-step optical excitation process which incorporates Stark switching to reach higher

l

states not normally accessible because of dipole selection rules. Quantum defects are reported for several

5{p}_{\frac{1}{2}}

\mathrm{ns}

and

5{p}_{\frac{1}{2}}

\mathrm{nd}

states. The lifetimes of the

5{p}_{\frac{1}{2}}

\mathrm{ns}

states are shown to scale as

{({n}^{*})}^{3}

, and the lifetimes of the

5{p}_{\frac{1}{2}}

16l

states are shown to increase dramatically with increasing

l

We have examined the ionization of

{\mathrm{Na}}_{2}

Rydberg states of principal quantum number n=11--16 converging to rotational-vibrational, v=3--6 and R10, states of

{\mathrm{Na}}_{2}^{+}

by 8-GHz microwave fields. Rydberg states lying below the lowest, v=0, R=0 (v and R are the vibrational and rotational quantum numbers of the molecular ion), ion limit of

{\mathrm{Na}}_{2}^{+}

are observed to ionize at approximately E=1/3

{\mathit{n}}_{0}^{5}

, where

{\mathit{n}}_{0}

is the effective quantum number relative to the v=R=0 limit. The agreement with this dependence is not nearly as good as in an atom, and the possible reasons for the deviations are discussed.