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

arXiv:1208.3649 · Physical Review A

Photoassociation to the 21Σg+ state in ultracold 85 Rb 2 in the presence of a shape resonance

Michael Bellos, Ryan Carollo, David Rahmlow, Jayita Banerjee, Edward E. Eyler, P. L. Gould, William C. Stwalley

Published Sep 7, 2012• 15 citations
arXivHTMLPDF

Abstract

We report the observation of photoassociation to the $2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}{\ensuremath{\Sigma}}_{g}^{+}$ state of ${}^{85}$Rb${}_{2}$. We have observed two vibrational levels (${v}^{\ensuremath{'}}=98,99$) below the $5{s}_{1/2}+5{p}_{1/2}$ atomic limit and 11 vibrational levels (${v}^{\ensuremath{'}}=102$--112) above it. The photoassociation---and subsequent spontaneous emission---occur predominantly between 15 and 20 bohrs in a region of internuclear distance best described as a transition between Hund's case (a) and Hund's case (c) coupling. The presence of a $g$-wave shape resonance in the collision of two ground-state atoms affects the photoassociation rate and line shape of the ${J}^{\ensuremath{'}}=3$ and 5 rotational levels.

DOI
10.1103/physreva.86.033407

Related papers

Observation and analysis of resonant coupling between nearly degenerate levels of the 21Σg+ and 11Πg states of ultracold 85 Rb 2

Ryan Carollo, Michael Bellos, David Rahmlow +4 more

We report on the anomalously high line strength of a single rotational level in the ultracold photoassociation of two ${}^{85}$Rb atoms to form ${}^{85}$Rb${}_{2}$. The ${v}^{\ensuremath{'}}=111$, ${J}^{\ensuremath{'}}=5$ level belongs to the Hund's case (c) $2\phantom{\rule{0.16em}{0ex}}({0}_{g}^{+})$ state, which correlates to the Hund's case (a) $2{\phantom{\rule{0.16em}{0ex}}}^{1}{\ensuremath{\Sigma}}_{g}^{+}$ state. Its strength is caused by coupling with a very near-resonant long-range state. The long-range component is the energetically degenerate ${v}^{\ensuremath{'}}=155$, ${J}^{\ensuremath{'}}=5$ level of the case (c) $2\phantom{\rule{0.16em}{0ex}}({1}_{g})$ state, correlating to the case (a) $1{\phantom{\rule{0.16em}{0ex}}}^{1}{\ensuremath{\Pi}}_{g}$ state. The line strength is enhanced by an order of magnitude through this coupling, relative to nearby vibrational levels and even to nearby rotational levels of the same vibrational level. This enhancement is in addition to the enhancement seen in all ${J}^{\ensuremath{'}}=3$ and 5 levels of the $2\phantom{\rule{0.16em}{0ex}}({0}_{g}^{+})$ state due to an $l=4$ shape resonance in the $a{\phantom{\rule{0.16em}{0ex}}}^{3}{\ensuremath{\Sigma}}_{u}^{+}$ state continuum, which alters the distribution of levels formed by photoassociation.

arXiv:1212.2990•Physical Review A•Feb 13, 2013•3 citations

Formation of ultracold Rb2 molecules in the v′′ = 0 level of the a3Σ+u state via blue-detuned photoassociation to the 13Πg state

Michael Bellos, David Rahmlow, Ryan Carollo +6 more

We report on the observation of blue-detuned photoassociation in Rb(2), in which vibrational levels are energetically above the corresponding excited atomic asymptote. (85)Rb atoms in a MOT were photoassociated at short internuclear distance to levels of the 1(3)Π(g) state at a rate of approximately 5 × 10(4) molecules s(-1). We have observed most of the predicted vibrational levels for all four spin-orbit components; 0(+)(g), 0(-)(g), 1(g), and 2(g), including levels of the 0(+)(g) outer well. These molecules decay to the metastable a(3)Σ(+)(u) state, some preferentially to the v'' = 0 level, as we have observed for photoassociation to the v' = 8 level of the 1(g) component.

Physical Chemistry Chemical Physics•Jan 1, 2011•36 citations

Formation of ultracold RbCs molecules by photoassociation

Nadia Bouloufa-Maafa, M Aymar, Olivier Dulieu +1 more

The formation of ultracold metastable RbCs molecules is observed in a double species magneto-optical trap through photoassociation below the 85 Rb(5S 1/2 ) + 133 Cs(6P 3/2 ) dissociation limit followed by spontaneous emission. The molecules are detected by resonance enhanced two-photon ionization. Using accurate quantum chemistry calculations of the potential energy curves and transition dipole moment, we interpret the observed photoassociation process as occurring at short internuclear distance, in contrast with most previous cold atom photoassociation studies. The vibrational levels excited by photoassociation belong to the 5th 0 + or the 4th 0 − electronic states correlated to the Rb(5P 1/2, 3/2 ) + Cs(6S 1/2 ) dissociation limit. The computed vibrational distribution of the produced molecules shows that they are stabilized in deeply bound vibrational states of the lowest triplet state. We also predict that a noticeable fraction of molecules is produced in the lowest level of the electronic ground state.

arXiv:1111.3503•Laser Physics•Sep 3, 2012•23 citations

Formation, detection and spectroscopy of ultracold Rb2in the ground X1Σg+state

Yanyan Huang, J Qi, Hyewon Pechkis +4 more

We form ultracold ground-state Rb 2 molecules by photoassociating pairs of atoms in a magneto-optical trap into the 0 u + state, which decays radiatively into high vibrational levels of the X 1 Σ g + state. Sensitive and vibrationally state-selective detection is achieved by means of resonantly-enhanced two-photon ionization with a pulsed laser. Frequency scans of the detection laser reveal a long vibrational progression to a previously unobserved electronic excited state, which we identify as the 2 1 Σ u + state. Most of its vibrational spectrum is in excellent agreement with predictions based on ab initio potentials, although the lowest vibrational levels exhibit strong perturbative mixing with the triplet 2 3 Π u state. The detection method reported here, with minor variations, should be effective for the entire potential well of the X state. In this work no transitions are observed from vibrational levels above v = 118, but this turns out to be a limitation not of the detection method but rather of the photoassociative formation scheme, due to re-excitation of the highest- v levels by the same photoassociation laser that produces them.

Journal of Physics B Atomic Molecular and Optical Physics•Sep 25, 2006•52 citations

Production and Detection of Ultracold Ground State 85 Rb 133 Cs Molecules in the Lowest Vibrational Level by Short-Range Photoassociation

Yanting Zhao, Jinpeng Yuan, Zhonghao Li +3 more

We investigate the production of ultracold ground state X 1 σ + (v = 0) RbCs molecules in the lowest vibrational level via short-range photoassociation followed by spontaneous emission. The starting point is the laser cooled 85 Rb and 133 Cs atoms in a dual species, forced dark magneto-optical trap. The special intermediate level (5)0 + (v = 10) correlated to the (2) 3 π electric state is achieved by the photoassociation process. The formed ground state X 1 σ + (v = 0) molecule is resonantly excited to the 2 1 π intermediate state by a 651 nm pulse laser and is ionized by a 532 nm pulse laser and then detected by the time-of-flight mass spectrum. Saturation of the photoionization spectroscopy at large ionization laser energy is observed and the ionization efficiency is obtained from the fitting. The production of ultracold ground state 85 Rb 133 Cs molecules is facilitative for the further research about the manipulation of ultracold molecules in the rovibrational ground state.

Chinese Physics Letters•Nov 1, 2015•3 citations

Enhancement of the formation of ultracold Rb285 molecules due to resonant coupling

Hyewon Pechkis, Dajun Wang, Yanyan Huang +4 more

We have studied the effect of resonant electronic-state coupling on the formation of ultracold ground-state $^{85}\mathrm{Rb}_{2}$. Ultracold ${\mathrm{Rb}}_{2}$ molecules are formed by photoassociation (PA) to a coupled pair of ${0}_{u}^{+}$ states, ${0}_{u}^{+}({P}_{1∕2})$ and ${0}_{u}^{+}({P}_{3∕2})$, in the region below the $5S+5{P}_{1∕2}$ limit. Subsequent radiative decay produces high vibrational levels of the ground state, $X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}$. The population distribution of these $X$-state vibrational levels is monitored by resonance-enhanced two-photon ionization through the $2\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{u}^{+}$ state. We find that the populations of vibrational levels ${v}^{\ensuremath{''}}=112--116$ are far larger than can be accounted for by the Franck-Condon factors for ${0}_{u}^{+}({P}_{1∕2})\ensuremath{\rightarrow}X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}$ transitions with the ${0}_{u}^{+}({P}_{1∕2})$ state treated as a single channel. Further, the ground-state molecule population exhibits oscillatory behavior as the PA laser is tuned through a succession of ${0}_{u}^{+}$ state vibrational levels. Both of these effects are explained by a calculation of transition amplitudes that includes the resonant character of the spin-orbit coupling of the two ${0}_{u}^{+}$ states. The resulting enhancement of more deeply bound ground-state molecule formation will be useful for future experiments on ultracold molecules.

arXiv:0707.2401•Physical Review A•Aug 22, 2007•33 citations
We report the observation of photoassociation to the 21\ensuremathΣg+2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}{\ensuremath{\Sigma}}_{g}^{+}21\ensuremathΣg+​ state of 85{}^{85}85Rb2{}_{2}2​. We have observed two vibrational levels (v\ensuremath′=98,99{v}^{\ensuremath{'}}=98,99v\ensuremath′=98,99) below the 5s1/2+5p1/25{s}_{1/2}+5{p}_{1/2}5s1/2​+5p1/2​ atomic limit and 11 vibrational levels (v\ensuremath′=102{v}^{\ensuremath{'}}=102v\ensuremath′=102--112) above it. The photoassociation---and subsequent spontaneous emission---occur predominantly between 15 and 20 bohrs in a region of internuclear distance best described as a transition between Hund's case (a) and Hund's case (c) coupling. The presence of a ggg-wave shape resonance in the collision of two ground-state atoms affects the photoassociation rate and line shape of the J\ensuremath′=3{J}^{\ensuremath{'}}=3J\ensuremath′=3 and 5 rotational levels.
We report on the anomalously high line strength of a single rotational level in the ultracold photoassociation of two 85{}^{85}85Rb atoms to form 85{}^{85}85Rb2{}_{2}2​. The ${v}^{\ensuremath{'}}=111$, ${J}^{\ensuremath{'}}=5$ level belongs to the Hund's case (c) 2(0g+)2\phantom{\rule{0.16em}{0ex}}({0}_{g}^{+})2(0g+​) state, which correlates to the Hund's case (a) $2{\phantom{\rule{0.16em}{0ex}}}^{1}{\ensuremath{\Sigma}}_{g}^{+}$ state. Its strength is caused by coupling with a very near-resonant long-range state. The long-range component is the energetically degenerate ${v}^{\ensuremath{'}}=155$, ${J}^{\ensuremath{'}}=5$ level of the case (c) 2(1g)2\phantom{\rule{0.16em}{0ex}}({1}_{g})2(1g​) state, correlating to the case (a) $1{\phantom{\rule{0.16em}{0ex}}}^{1}{\ensuremath{\Pi}}_{g}$ state. The line strength is enhanced by an order of magnitude through this coupling, relative to nearby vibrational levels and even to nearby rotational levels of the same vibrational level. This enhancement is in addition to the enhancement seen in all ${J}^{\ensuremath{'}}=3$ and 5 levels of the 2(0g+)2\phantom{\rule{0.16em}{0ex}}({0}_{g}^{+})2(0g+​) state due to an l=4l=4l=4 shape resonance in the $a{\phantom{\rule{0.16em}{0ex}}}^{3}{\ensuremath{\Sigma}}_{u}^{+}$ state continuum, which alters the distribution of levels formed by photoassociation.
We report on the observation of blue-detuned photoassociation in Rb(2), in which vibrational levels are energetically above the corresponding excited atomic asymptote. (85)Rb atoms in a MOT were photoassociated at short internuclear distance to levels of the 1(3)Π(g) state at a rate of approximately 5 × 10(4) molecules s(-1). We have observed most of the predicted vibrational levels for all four spin-orbit components; 0(+)(g), 0(-)(g), 1(g), and 2(g), including levels of the 0(+)(g) outer well. These molecules decay to the metastable a(3)Σ(+)(u) state, some preferentially to the v'' = 0 level, as we have observed for photoassociation to the v' = 8 level of the 1(g) component.
The formation of ultracold metastable RbCs molecules is observed in a double species magneto-optical trap through photoassociation below the 85 Rb(5S 1/2 ) + 133 Cs(6P 3/2 ) dissociation limit followed by spontaneous emission. The molecules are detected by resonance enhanced two-photon ionization. Using accurate quantum chemistry calculations of the potential energy curves and transition dipole moment, we interpret the observed photoassociation process as occurring at short internuclear distance, in contrast with most previous cold atom photoassociation studies. The vibrational levels excited by photoassociation belong to the 5th 0 + or the 4th 0 − electronic states correlated to the Rb(5P 1/2, 3/2 ) + Cs(6S 1/2 ) dissociation limit. The computed vibrational distribution of the produced molecules shows that they are stabilized in deeply bound vibrational states of the lowest triplet state. We also predict that a noticeable fraction of molecules is produced in the lowest level of the electronic ground state.
We form ultracold ground-state Rb 2 molecules by photoassociating pairs of atoms in a magneto-optical trap into the 0 u + state, which decays radiatively into high vibrational levels of the X 1 Σ g + state. Sensitive and vibrationally state-selective detection is achieved by means of resonantly-enhanced two-photon ionization with a pulsed laser. Frequency scans of the detection laser reveal a long vibrational progression to a previously unobserved electronic excited state, which we identify as the 2 1 Σ u + state. Most of its vibrational spectrum is in excellent agreement with predictions based on ab initio potentials, although the lowest vibrational levels exhibit strong perturbative mixing with the triplet 2 3 Π u state. The detection method reported here, with minor variations, should be effective for the entire potential well of the X state. In this work no transitions are observed from vibrational levels above v = 118, but this turns out to be a limitation not of the detection method but rather of the photoassociative formation scheme, due to re-excitation of the highest- v levels by the same photoassociation laser that produces them.
We investigate the production of ultracold ground state X 1 σ + (v = 0) RbCs molecules in the lowest vibrational level via short-range photoassociation followed by spontaneous emission. The starting point is the laser cooled 85 Rb and 133 Cs atoms in a dual species, forced dark magneto-optical trap. The special intermediate level (5)0 + (v = 10) correlated to the (2) 3 π electric state is achieved by the photoassociation process. The formed ground state X 1 σ + (v = 0) molecule is resonantly excited to the 2 1 π intermediate state by a 651 nm pulse laser and is ionized by a 532 nm pulse laser and then detected by the time-of-flight mass spectrum. Saturation of the photoionization spectroscopy at large ionization laser energy is observed and the ionization efficiency is obtained from the fitting. The production of ultracold ground state 85 Rb 133 Cs molecules is facilitative for the further research about the manipulation of ultracold molecules in the rovibrational ground state.
We have studied the effect of resonant electronic-state coupling on the formation of ultracold ground-state 85Rb2^{85}\mathrm{Rb}_{2}85Rb2​. Ultracold Rb2{\mathrm{Rb}}_{2}Rb2​ molecules are formed by photoassociation (PA) to a coupled pair of 0u+{0}_{u}^{+}0u+​ states, 0u+(P1∕2){0}_{u}^{+}({P}_{1∕2})0u+​(P1∕2​) and 0u+(P3∕2){0}_{u}^{+}({P}_{3∕2})0u+​(P3∕2​), in the region below the 5S+5P1∕25S+5{P}_{1∕2}5S+5P1∕2​ limit. Subsequent radiative decay produces high vibrational levels of the ground state, $X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}$. The population distribution of these XXX-state vibrational levels is monitored by resonance-enhanced two-photon ionization through the $2\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{u}^{+}$ state. We find that the populations of vibrational levels ${v}^{\ensuremath{''}}=112--116$ are far larger than can be accounted for by the Franck-Condon factors for ${0}_{u}^{+}({P}_{1∕2})\ensuremath{\rightarrow}X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}$ transitions with the 0u+(P1∕2){0}_{u}^{+}({P}_{1∕2})0u+​(P1∕2​) state treated as a single channel. Further, the ground-state molecule population exhibits oscillatory behavior as the PA laser is tuned through a succession of 0u+{0}_{u}^{+}0u+​ state vibrational levels. Both of these effects are explained by a calculation of transition amplitudes that includes the resonant character of the spin-orbit coupling of the two 0u+{0}_{u}^{+}0u+​ states. The resulting enhancement of more deeply bound ground-state molecule formation will be useful for future experiments on ultracold molecules.