Physical Review Letters

Highly Excited States of Ultracold Molecules: Photoassociative Spectroscopy of Na2

James P. Shaffer, Witek Chalupczak, N. P. Bigelow

Published Nov 1, 1999• 15 citations

Abstract

We describe the spectroscopy of highly excited states of ultracold ${\mathrm{Na}}_{2}$ molecules using a new photoassociative approach based on resonantly enhanced multiphoton ionization. We excite a remarkable number of ${\mathrm{Na}}_{2}$ rotational states providing a rich rovibrational spectrum. We thereby extract not only the first order quadrupole-quadrupole ( ${C}_{5}$) and the van der Waals constants ( ${C}_{6}$) but also sensitive atom-atom interaction parameters such as spin-spin, spin-orbit, and perturbative constants.

DOI: 10.1103/physrevlett.83.3621

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Physical Review Letters

Highly Excited States of Ultracold Molecules: Photoassociative Spectroscopy of Na2

James P. Shaffer, Witek Chalupczak, N. P. Bigelow

Published Nov 1, 1999• 15 citations

Publisher

Abstract

We describe the spectroscopy of highly excited states of ultracold

{\mathrm{Na}}_{2}

molecules using a new photoassociative approach based on resonantly enhanced multiphoton ionization. We excite a remarkable number of

{\mathrm{Na}}_{2}

rotational states providing a rich rovibrational spectrum. We thereby extract not only the first order quadrupole-quadrupole (

{C}_{5}

) and the van der Waals constants (

{C}_{6}

) but also sensitive atom-atom interaction parameters such as spin-spin, spin-orbit, and perturbative constants.

DOI: 10.1103/physrevlett.83.3621

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

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 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.

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The electrostatic interaction between an excited atom and a diatomic ground-state molecule in an arbitrary rovibrational level at large mutual separations is investigated with a general second-order perturbation theory, in the perspective of modeling the photoassociation between cold atoms and molecules. We find that the combination of quadrupole-quadrupole and van der Waals interactions competes with the rotational energy of the dimer, limiting the range of validity of the perturbative approach to distances larger than 100 Bohr radii. Numerical results are given for the long-range interaction between Cs and Cs ${}_{2}$ , showing that the photoassociation is probably efficient for any Cs ${}_{2}$ rotational energy.The electrostatic interaction between an excited atom and a diatomic ground-state molecule in an arbitrary rovibrational level at large mutual separations is investigated with a general second-order perturbation theory, in the perspective of modeling the photoassociation between cold atoms and molecules. We find that the combination of quadrupole-quadrupole and van der Waals interactions competes with the rotational energy of the dimer, limiting the range of validity of the perturbative approach to distances larger than 100 Bohr radii. Numerical results are given for the long-range interaction between Cs and Cs${}_{2}$, showing that the photoassociation is probably efficient for any Cs${}_{2}$ rotational energy.

arXiv:1101.0542Physical Review AApr 12, 201116 citations

We describe the spectroscopy of highly excited states of ultracold

{\mathrm{Na}}_{2}

molecules using a new photoassociative approach based on resonantly enhanced multiphoton ionization. We excite a remarkable number of

{\mathrm{Na}}_{2}

rotational states providing a rich rovibrational spectrum. We thereby extract not only the first order quadrupole-quadrupole (

{C}_{5}

) and the van der Waals constants (

{C}_{6}

) but also sensitive atom-atom interaction parameters such as spin-spin, spin-orbit, and perturbative constants.

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 have observed the spectrum of long range molecular states of singly excited

{\mathrm{Na}}_{2}

formed by photoassociation during ultracold associative ionization collisions of laser-cooled Na atoms. The low kinetic energy of the collision allows us to obtain very high resolution spectra and to observe states close to the dissociation limit. The spectrum shows regular vibrational series characteristic of the 1/

{\mathit{R}}^{3}

long range portion of the

{1}_{\mathit{g}}

potential (asymptotically

{\mathit{S}}_{1/2}

{\mathit{P}}_{3/2}

) as well as molecular hyperfine structure within these peaks. We extract potential parameters and compare with recent theory.

{}_{2}

, showing that the photoassociation is probably efficient for any Cs

{}_{2}

rotational energy.