Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Photoassociative Spectroscopy of Collisions Between Ultracold Lithium Atoms

E. Abraham

Published Jan 1, 1996• 0 citations
OpenAlex

Abstract

The spectra of the high-lying vibrational levels of the $A\\sp1\\Sigma\\sbsp{u}{+}$ and $1\\sp3\\Sigma\\sbsp{g}{+}$ singly excited states of both $\\sp6\\rm Li\\sb2$ and $\\sp7\\rm Li\\sb2$ are obtained via photoassociation of colliding ultracold atoms confined in a magneto-optical trap. The least bound state of the $a\\sp3\\Sigma\\sbsp{u}{+}$ ground state potential, obtained by two-photon photoassociative spectroscopy, is also presented for both $\\sp7\\rm Li\\sb2$ and $\\sp6\\rm Li\\sb2$. The vibrational levels have resolved hyperfine structure, whose relative energy splittings and transition strengths are accurately modeled. The photoassociative spectra are used to precisely determine both the singlet and triplet s-wave scattering lengths for both isotopes, which are important parameters in systems designed to observe quantum degenerate effects and Bose-Einstein condensation.

Related papers

Photoassociative spectroscopy of ultracold lithium(2)-7 and lithium(2)-6

E. Abraham

We have obtained high-lying vibrational spectra for the $\\rm 1\\sp3\\Sigma\\sbsp{g}{+}$ and $\\rm 1\\sp1\\Sigma\\sbsp{u}{+}$ excited states of both $\\rm \\sp7Li\\sb2$ and $\\rm \\sp6Li\\sb2$ via photoassociation of colliding ultracold lithium atoms confined in a magneto-optical trap. Photoassociative spectroscopy of ultracold atoms is a powerful tool for probing molecular states near the dissociation energy that are inaccessible by other methods. For an ultracold lithium vapor, the distribution of unbound ground state energies is so small that precise free-bound spectroscopy is possible. Molecular hyperfine structure is resolved. We calculate accurate dissociation energies for both the $\\rm 1\\sp3\\Sigma\\sbsp{g}{+}$ and $\\rm 1\\sp1\\Sigma\\sbsp{u}{+}$ excited states of Li$\\sb2$. A model potential is constructed from a combination of experimental and theoretical information, and used to assign vibrational quantum numbers. We observe rotational structure and assign rotational quantum numbers.

•Jan 1, 1995•0 citations

Hyperfine structure in photoassociative spectra of Li26 and Li27

E. R. I. Abraham, W. I. McAlexander, Henk T. C. Stoof +1 more

We present spectra of hyperfine resolved vibrational levels of the ${\mathit{A}}^{1}$${\mathrm{\ensuremath{\Sigma}}}_{\mathit{u}}^{+}$and 1${\mathrm{}}^{3}$${\mathrm{\ensuremath{\Sigma}}}_{\mathit{g}}^{+}$ states of $^{6}\mathrm{Li}_{2}$ and $^{7}\mathrm{Li}_{2}$ obtained via photoassociation of colliding ultracold atoms in a magneto-optical trap. A simple first-order perturbation theory analysis accurately accounts for the frequency splittings and relative transition strengths of all observed hyperfine features. Assignment of the hyperfine structure allows accurate determination of a vibrational level center of gravity, which significantly decreases the experimental uncertainty of vibrational energies. Differences in the spectra of $^{6}\mathrm{Li}_{2}$ and $^{7}\mathrm{Li}_{2}$ are attributed to quantum statistics. The 1${\mathrm{}}^{3}$${\mathrm{\ensuremath{\Sigma}}}_{\mathit{g}}^{+}$ series obeys Hund's case ${\mathit{b}}_{\mathrm{\ensuremath{\beta}}\mathit{S}}$ coupling and the hyperfine constant is extracted for both isotopes. \textcopyright{} 1996 The American Physical Society.

Physical Review A•May 1, 1996•27 citations

Singlet s-wave scattering lengths of {sup 6}Li and {sup 7}Li

E. Abraham, W. I. McAlexander, Jordan M. Gerton

Ultracold collisional interactions are crucial to both the dynamical evolution and the steady-state behavior of systems designed to observe Bose-Einstein condensation, and are relevant to the advances in high precision measurements, and the creation of more highly accurate atomic clocks based on laser-cooled neutral atoms. An important parameter for understanding these collisions is the s-wave scattering length {alpha}, which can be determined from accurate knowledge of the two-body interaction potential. Photoassociation of ultracold lithium atoms into bound vibrational levels of the A{sup 1}{Sigma}{sub u}{sup +} excited state is used to probe the X{sup 1}{Sigma}{sub g}{sup +} ground state interaction potential of {sup 6}Li{sub 2} and {sup 7}Li{sub 2}. It had been predicted that the s-wave photoassociation signal strength would pass through a minimum as a function of vibrational level for positive scattering length. The authors present the observation of this novel effect, and use the location of the minimum to precisely determine the singlet s-wave scattering length for both isotopes. The sensitivity of this technique is demonstrated by distinguishing the scattering lengths for collisions involving {sup 7}Li atoms in different hyperfine states.

Bulletin of the American Physical Society•May 1, 1996•0 citations

Singlet s -wave scattering lengths of Li6 and Li7

E. R. I. Abraham, W. I. McAlexander, Jordan M. Gerton +3 more

Photoassociation of ultracold lithium atoms into bound vibrational levels of the $A^{1}\ensuremath{\Sigma}_{u}^{+}$ excited state is used to probe the $X^{1}\ensuremath{\Sigma}_{g}^{+}$ ground-state interaction potential of $^{6}\mathrm{Li}_{2}$ and $^{7}\mathrm{Li}_{2}$. It had been predicted that the $s$-wave photoassociation signal strength would pass through a minimum as a function of vibrational level for positive $s$-wave scattering length. We report the observation of this novel effect, and use the location of the minimum to precisely determine the singlet $s$-wave scattering length for both isotopes. The sensitivity of this technique is demonstrated by distinguishing the minima for collisions involving $^{7}\mathrm{Li}$ atoms in different hyperfine states.

Physical Review A•Jun 1, 1996•51 citations

Photoassociative spectroscopy of long-range states of ultracold 6Li2 and 7Li2

E. R. I. Abraham, Nicholas W. M. Ritchie, W. I. McAlexander +1 more

We have obtained spectra of the high-lying vibrational levels of the A1Σu+ and 13Σg+states of both 6Li2 and 7Li2 via photoassociation of colliding ultracold atoms confined to a magneto-optical trap. Because of the low collision energies (∼1 mK), very high spectroscopic resolution is realized, and sensitivity is greatest for the usually difficult to access long-range states. Binding energies relative to the center of gravity of the resolved hyperfine structure are given for the A1Σu+ vibrational levels v =62–88 for 6Li2 and v=65–97 for 7Li2, and the 13Σg+ vibrational levels v=56–84 for 6Li2 and v=62–90 for 7Li2. These are extremely long-range levels with outer classical turning points ranging from 25 a0 to 220 a0, where a0 is the Bohr radius. The spectra arise mainly from s-wave collisions, and therefore exhibit little rotational structure.

The Journal of Chemical Physics•Nov 8, 1995•91 citations

Precise determination of the 2P radiative atomic lifetime of lithium using photoassociative spectroscopy

W. I. McAlexander

Spectroscopy of the high-lying vibrational levels of the $1\\sp3\\Sigma\\sbsp{g}{+}$ and $1\\sp1\\Sigma\\sbsp{u}{+}$ states of both $\\rm\\sp6Li\\sb2$ and $\\rm\\sp7Li\\sb2$ has been accomplished via photoassociation of ultracold atomic lithium confined in a magneto-optical trap. Both these molecular states correlate to $2S\\sb{1/2}$ plus $2P\\sb{1/2}$ free atomic states. The long range part of these molecular potentials depends on the 2P atomic radiative lifetime. Accurate models were constructed for both the $1\\sp3\\Sigma\\sbsp{g}{+}$ and $1\\sp1\\Sigma\\sbsp{u}{+}$ potentials. By fitting these models to the experimentally measured vibrational levels observed in $\\rm\\sp6Li\\sb2$ and $\\rm\\sp7Li\\sb2$, we have been able to extract a value for the 2P lifetime of lithium. Fitting to the absolute values of the data gives a value of 26.99 $\\pm$ 0.16 ns whereas fitting to differences in the spectral features gives a value of 27.04 $\\pm$ 0.18 ns. While both values agree with previous work, improvements made in the potential models would enable this analysis to resolve the current discrepancy between experiment and theory.

•Jan 1, 1995•0 citations
The spectra of the high-lying vibrational levels of the Asp1Sigmasbspu+A\\sp1\\Sigma\\sbsp{u}{+}Asp1Sigmasbspu+ and 1sp3Sigmasbspg+1\\sp3\\Sigma\\sbsp{g}{+}1sp3Sigmasbspg+ singly excited states of both sp6rmLisb2\\sp6\\rm Li\\sb2sp6rmLisb2 and sp7rmLisb2\\sp7\\rm Li\\sb2sp7rmLisb2 are obtained via photoassociation of colliding ultracold atoms confined in a magneto-optical trap. The least bound state of the asp3Sigmasbspu+a\\sp3\\Sigma\\sbsp{u}{+}asp3Sigmasbspu+ ground state potential, obtained by two-photon photoassociative spectroscopy, is also presented for both sp7rmLisb2\\sp7\\rm Li\\sb2sp7rmLisb2 and sp6rmLisb2\\sp6\\rm Li\\sb2sp6rmLisb2. The vibrational levels have resolved hyperfine structure, whose relative energy splittings and transition strengths are accurately modeled. The photoassociative spectra are used to precisely determine both the singlet and triplet s-wave scattering lengths for both isotopes, which are important parameters in systems designed to observe quantum degenerate effects and Bose-Einstein condensation.
We have obtained high-lying vibrational spectra for the rm1sp3Sigmasbspg+\\rm 1\\sp3\\Sigma\\sbsp{g}{+}rm1sp3Sigmasbspg+ and rm1sp1Sigmasbspu+\\rm 1\\sp1\\Sigma\\sbsp{u}{+}rm1sp1Sigmasbspu+ excited states of both rmsp7Lisb2\\rm \\sp7Li\\sb2rmsp7Lisb2 and rmsp6Lisb2\\rm \\sp6Li\\sb2rmsp6Lisb2 via photoassociation of colliding ultracold lithium atoms confined in a magneto-optical trap. Photoassociative spectroscopy of ultracold atoms is a powerful tool for probing molecular states near the dissociation energy that are inaccessible by other methods. For an ultracold lithium vapor, the distribution of unbound ground state energies is so small that precise free-bound spectroscopy is possible. Molecular hyperfine structure is resolved. We calculate accurate dissociation energies for both the rm1sp3Sigmasbspg+\\rm 1\\sp3\\Sigma\\sbsp{g}{+}rm1sp3Sigmasbspg+ and rm1sp1Sigmasbspu+\\rm 1\\sp1\\Sigma\\sbsp{u}{+}rm1sp1Sigmasbspu+ excited states of Lisb2\\sb2sb2. A model potential is constructed from a combination of experimental and theoretical information, and used to assign vibrational quantum numbers. We observe rotational structure and assign rotational quantum numbers.
We present spectra of hyperfine resolved vibrational levels of the A1{\mathit{A}}^{1}A1${\mathrm{\ensuremath{\Sigma}}}_{\mathit{u}}^{+}$and 13{\mathrm{}}^{3}3${\mathrm{\ensuremath{\Sigma}}}_{\mathit{g}}^{+}$ states of 6Li2^{6}\mathrm{Li}_{2}6Li2​ and 7Li2^{7}\mathrm{Li}_{2}7Li2​ obtained via photoassociation of colliding ultracold atoms in a magneto-optical trap. A simple first-order perturbation theory analysis accurately accounts for the frequency splittings and relative transition strengths of all observed hyperfine features. Assignment of the hyperfine structure allows accurate determination of a vibrational level center of gravity, which significantly decreases the experimental uncertainty of vibrational energies. Differences in the spectra of 6Li2^{6}\mathrm{Li}_{2}6Li2​ and 7Li2^{7}\mathrm{Li}_{2}7Li2​ are attributed to quantum statistics. The 13{\mathrm{}}^{3}3${\mathrm{\ensuremath{\Sigma}}}_{\mathit{g}}^{+}$ series obeys Hund's case ${\mathit{b}}_{\mathrm{\ensuremath{\beta}}\mathit{S}}$ coupling and the hyperfine constant is extracted for both isotopes. \textcopyright{} 1996 The American Physical Society.
Ultracold collisional interactions are crucial to both the dynamical evolution and the steady-state behavior of systems designed to observe Bose-Einstein condensation, and are relevant to the advances in high precision measurements, and the creation of more highly accurate atomic clocks based on laser-cooled neutral atoms. An important parameter for understanding these collisions is the s-wave scattering length {alpha}, which can be determined from accurate knowledge of the two-body interaction potential. Photoassociation of ultracold lithium atoms into bound vibrational levels of the A{sup 1}{Sigma}{sub u}{sup +} excited state is used to probe the X{sup 1}{Sigma}{sub g}{sup +} ground state interaction potential of {sup 6}Li{sub 2} and {sup 7}Li{sub 2}. It had been predicted that the s-wave photoassociation signal strength would pass through a minimum as a function of vibrational level for positive scattering length. The authors present the observation of this novel effect, and use the location of the minimum to precisely determine the singlet s-wave scattering length for both isotopes. The sensitivity of this technique is demonstrated by distinguishing the scattering lengths for collisions involving {sup 7}Li atoms in different hyperfine states.
Photoassociation of ultracold lithium atoms into bound vibrational levels of the $A^{1}\ensuremath{\Sigma}_{u}^{+}$ excited state is used to probe the $X^{1}\ensuremath{\Sigma}_{g}^{+}$ ground-state interaction potential of 6Li2^{6}\mathrm{Li}_{2}6Li2​ and 7Li2^{7}\mathrm{Li}_{2}7Li2​. It had been predicted that the sss-wave photoassociation signal strength would pass through a minimum as a function of vibrational level for positive sss-wave scattering length. We report the observation of this novel effect, and use the location of the minimum to precisely determine the singlet sss-wave scattering length for both isotopes. The sensitivity of this technique is demonstrated by distinguishing the minima for collisions involving 7Li^{7}\mathrm{Li}7Li atoms in different hyperfine states.
We have obtained spectra of the high-lying vibrational levels of the A1Σu+ and 13Σg+states of both 6Li2 and 7Li2 via photoassociation of colliding ultracold atoms confined to a magneto-optical trap. Because of the low collision energies (∼1 mK), very high spectroscopic resolution is realized, and sensitivity is greatest for the usually difficult to access long-range states. Binding energies relative to the center of gravity of the resolved hyperfine structure are given for the A1Σu+ vibrational levels v =62–88 for 6Li2 and v=65–97 for 7Li2, and the 13Σg+ vibrational levels v=56–84 for 6Li2 and v=62–90 for 7Li2. These are extremely long-range levels with outer classical turning points ranging from 25 a0 to 220 a0, where a0 is the Bohr radius. The spectra arise mainly from s-wave collisions, and therefore exhibit little rotational structure.
Spectroscopy of the high-lying vibrational levels of the 1sp3Sigmasbspg+1\\sp3\\Sigma\\sbsp{g}{+}1sp3Sigmasbspg+ and 1sp1Sigmasbspu+1\\sp1\\Sigma\\sbsp{u}{+}1sp1Sigmasbspu+ states of both rmsp6Lisb2\\rm\\sp6Li\\sb2rmsp6Lisb2 and rmsp7Lisb2\\rm\\sp7Li\\sb2rmsp7Lisb2 has been accomplished via photoassociation of ultracold atomic lithium confined in a magneto-optical trap. Both these molecular states correlate to 2Ssb1/22S\\sb{1/2}2Ssb1/2 plus 2Psb1/22P\\sb{1/2}2Psb1/2 free atomic states. The long range part of these molecular potentials depends on the 2P atomic radiative lifetime. Accurate models were constructed for both the 1sp3Sigmasbspg+1\\sp3\\Sigma\\sbsp{g}{+}1sp3Sigmasbspg+ and 1sp1Sigmasbspu+1\\sp1\\Sigma\\sbsp{u}{+}1sp1Sigmasbspu+ potentials. By fitting these models to the experimentally measured vibrational levels observed in rmsp6Lisb2\\rm\\sp6Li\\sb2rmsp6Lisb2 and rmsp7Lisb2\\rm\\sp7Li\\sb2rmsp7Lisb2, we have been able to extract a value for the 2P lifetime of lithium. Fitting to the absolute values of the data gives a value of 26.99 pm\\pmpm 0.16 ns whereas fitting to differences in the spectral features gives a value of 27.04 pm\\pmpm 0.18 ns. While both values agree with previous work, improvements made in the potential models would enable this analysis to resolve the current discrepancy between experiment and theory.