We study the photoassociative collisional loss of laser-cooled Rb atoms from a far-off resonance optical dipole force atom trap. We obtain a well-resolved photoassociation spectrum from 50 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ to 980 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ below the first excited dissociation limit of the ${\mathrm{Rb}}_{2}$ molecule. Two vibrational series associated with excited ${\mathrm{Rb}}_{2}$ $^{3}\mathrm{\ensuremath{\Sigma}}_{\mathit{g}}^{+}$ states are clearly visible. Oscillations in the associated Franck-Condon factors reflect the structure of the triplet ground state wave function. Our results clearly demonstrate the potential of photoassociation spectroscopy as a new probe of molecular structure.We study the photoassociative collisional loss of laser-cooled Rb atoms from a far-off resonance optical dipole force atom trap. We obtain a well-resolved photoassociation spectrum from 50 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ to 980 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ below the first excited dissociation limit of the ${\mathrm{Rb}}_{2}$ molecule. Two vibrational series associated with excited ${\mathrm{Rb}}_{2}$ $^{3}\mathrm{\ensuremath{\Sigma}}_{\mathit{g}}^{+}$ states are clearly visible. Oscillations in the associated Franck-Condon factors reflect the structure of the triplet ground state wave function. Our results clearly demonstrate the potential of photoassociation spectroscopy as a new probe of molecular structure.

Physical Review LettersOct 4, 1993240 citations

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.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, 19950 citations

Relativistic calculations of ground and excited states of LiYb molecule for ultracold photoassociation spectroscopy studies

Geetha Gopakumar, Minori Abe, Bhanu Pratap Das +2 more

We report a series of quantum-chemical calculations for the ground and some of the low-lying excited states of an isolated LiYb molecule by the spin-orbit multistate complete active space second-order perturbation theory (SO-MS-CASPT2). Potential energy curves, spectroscopic constants, and transition dipole moments (TDMs) at both spin-free and spin-orbit levels are obtained. Large spin-orbit effects especially in the TDMs of the molecular states dissociating to Yb((3)P(0,1,2)) excited states are found. To ensure the reliability of our calculations, we test five types of incremental basis sets and study their effect on the equilibrium distance and dissociation energy of the ground state. We also compare CASPT2 and CCSD(T) results for the ground state spectroscopic constants at the spin-free relativistic level. The discrepancies between the CASPT2 and CCSD(T) results are only 0.01 Å in equilibrium bond distance (R(e)) and 200 cm(-1) in dissociation energy (D(e)). Our CASPT2 calculation in the supermolecular state (R=100 a.u.) with the largest basis set reproduces experimental atomic excitation energies within 3% error. Transition dipole moments of the super molecular state (R=100 a.u.) dissociating to Li((2)P) excited states are quite close to experimental atomic TDMs as compared to the Yb((3)P) and Yb((1)P) excited states. The information obtained from this work would be useful for ultracold photoassociation experiments on LiYb.We report a series of quantum-chemical calculations for the ground and some of the low-lying excited states of an isolated LiYb molecule by the spin-orbit multistate complete active space second-order perturbation theory (SO-MS-CASPT2). Potential energy curves, spectroscopic constants, and transition dipole moments (TDMs) at both spin-free and spin-orbit levels are obtained. Large spin-orbit effects especially in the TDMs of the molecular states dissociating to Yb((3)P(0,1,2)) excited states are found. To ensure the reliability of our calculations, we test five types of incremental basis sets and study their effect on the equilibrium distance and dissociation energy of the ground state. We also compare CASPT2 and CCSD(T) results for the ground state spectroscopic constants at the spin-free relativistic level. The discrepancies between the CASPT2 and CCSD(T) results are only 0.01 Å in equilibrium bond distance (R(e)) and 200 cm(-1) in dissociation energy (D(e)). Our CASPT2 calculation in the supermolecular state (R=100 a.u.) with the largest basis set reproduces experimental atomic excitation energies within 3% error. Transition dipole moments of the super molecular state (R=100 a.u.) dissociating to Li((2)P) excited states are quite close to experimental atomic TDMs as compared to the Yb((3)P) and Yb((1)P) excited states. The information obtained from this work would be useful for ultracold photoassociation experiments on LiYb.

The Journal of Chemical PhysicsSep 28, 201039 citations

Photoassociation spectroscopy of ultracold and Bose- condensed atomic gasses

R. S. Freeland

Sep 1, 20010 citations

{\mathrm{Rb}}_{2}

molecule. Two vibrational series associated with excited

{\mathrm{Rb}}_{2}

$^{3}\mathrm{\ensuremath{\Sigma}}_{\mathit{g}}^{+}$ states are clearly visible. Oscillations in the associated Franck-Condon factors reflect the structure of the triplet ground state wave function. Our results clearly demonstrate the potential of photoassociation spectroscopy as a new probe of molecular structure.

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.