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

Journal of Physics B Atomic Molecular and Optical Physics

Spectra of ultracold KRb molecules in near-dissociation vibrational levels

Dajun Wang, Edward E. Eyler, P. L. Gould, William C. Stwalley

Published Sep 25, 2006• 20 citations
Publisher

Abstract

We have studied resonance-enhanced two-photon ionization of ultracold 39 K 85 Rb molecules in highly excited long-range vibrational levels of the X 1 Σ + and a 3 Σ + states. These molecules are formed by photoassociation (PA) of ultracold 39 K and 85 Rb atoms, followed by spontaneous emission to the X 1 Σ + and a 3 Σ + states. In the range 15 500–17 200 cm −1 , we observe many intermediate and long-range levels of the previously unobserved 4 3 Σ + and 4 1 Σ + states and evidence for the onset of the previously unobserved 3 3 Π state. The observed vibrational spectra of these states are in very good agreement with calculated vibrational levels based on the ab initio potentials of Rousseau, Allouche and Aubert-Frécon. Such experiments illustrate some of the unique advantages of using PA-produced ultracold molecules for investigation of long-range vibrational levels and long-range forces, and for unravelling dense spectra because only a few rotational levels are populated.

DOI
10.1088/0953-4075/39/19/s03

Related papers

State-selective detection of near-dissociation ultracold KRb X Σ + 1 and a Σ + 3 molecules

Dajun Wang, Edward E. Eyler, P. L. Gould +1 more

We report on the state-selective detection of near-dissociation ultracold KRb molecules in the ground $X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}^{+}$ state and the metastable $a\phantom{\rule{0.2em}{0ex}}^{3}\ensuremath{\Sigma}^{+}$ state. The molecules are produced by photoassociation of ultracold atoms followed by radiative decay into high vibrational levels of the $X$ and $a$ states. Detection utilizes resonance-enhanced one-color two-photon ionization, followed by time-of-flight mass spectroscopy. Scanning the detection laser frequency over the range $582--625\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, we observe transitions from the ${v}^{\ensuremath{''}}=86--92$ levels of the $X$ state, which are bound by up to $30\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$, and the ${v}^{\ensuremath{''}}=17--23$ levels of the $a$ state, which are also bound by up to $30\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$. The measured vibrational spacings are in excellent agreement with those previously measured and those calculated from the relevant potential curves. Relative vibrational populations are also consistent with Franck-Condon factors for decay from the photoassociated levels.

arXiv:physics/0506232•Physical Review A•Sep 13, 2005•28 citations

Spectroscopy and applications of the 3 3Σ+ electronic state of 39K85Rb

Jayita Banerjee, David Rahmlow, Ryan Carollo +4 more

We report new results on the spectroscopy of the 3 (3)Σ(+) electronic state of (39)K(85)Rb. The observations are based on resonance-enhanced multiphoton ionization of ultracold KRb molecules starting in vibrational levels v'' = 18-23 of the a (3)Σ(+) state and ionized via the intermediate 3 (3)Σ(+) state. The a-state ultracold molecules are formed by photoassociation of ultracold (39)K and (85)Rb atoms to the 3(0(+)) state of KRb followed by spontaneous emission. We discuss the potential applications of this state to future experiments, as a pathway for populating the lowest vibrational levels of the a state as well as the X state.

The Journal of Chemical Physics•Nov 6, 2013•7 citations

Spectroscopic investigation of the A and 3 1Σ+ states of 39K85Rb

Jin‐Tae Kim, Yonghoon Lee, Bongsoo Kim +4 more

By using a combination of molecular beam (MB) excitation spectra and two distinct ultracold molecule excitation spectra (UM+ and UM-), we have assigned high vibrational levels of the A and 3 (1)Σ(+) states from absorption spectra of the mutually strongly perturbed A (1)Σ(+) - 3 (1)Σ(+) - 1 (1)Π - 2 (3)Σ(+) - b (3)Π states of ultracold (39)K(85)Rb molecules in the energy region between 15,116 and 16,225 cm(-1) above the minimum of the ground X (1)Σ(+) state. The ultracold molecules (UM+ and UM-) are formed by radiative decay following photoassociation (PA) to a specific level of the 3(0(+)) state (UM+) or to a specific level of the 3(0(-)) state (UM-). We observe that the A and 3 (1)Σ(+) states are observable in the UM+ spectra, but absent from the UM- spectra. This is explained by considering Hund's case (c) selection rules and transition dipole moments between the upper excited A (1)Σ(+) (2(0(+))) state and the three Ω components (0(+), 0(-), and 1) at the ground-state dissociation limit. We propose further investigations of the extended potential wells of the A and 3 (1)Σ(+) states by combining short-range MB excitation spectra in a narrow Franck-Condon (FC) window near R(e) of the X (1)Σ(+) state, and long-range UM (and PA) excitation spectra, which have much larger FC windows.

The Journal of Chemical Physics•Dec 26, 2012•9 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 of ultracold heteronuclear KRb molecules

Dajun Wang

This thesis describes the spectroscopy work on ultracold 39K 85Rb molecules as part of our effort towards producing ground-state ultracold polar molecules. ^ The starting points of our experiment are laser cooled and trapped K and Rb atoms in dual-species MOTs and the molecule formation method is photoassociation (PA). A fraction of the PA-produced excited-state molecules can spontaneously emit to the two lowest electronic states, the X 1Σ + state and the a 3Σ + state, to form high vibrational level molecules. In order to develop a population transfer scheme to make deeply bound molecules, we have studied the spectroscopy of KRb in several steps. Besides the PA step, we have also carried out a state-selective detection experiment to study the population distribution of the high vibrational level molecules formed via spontaneous emission. The detection method is pulsed-laser based ion time-of-flight mass spectroscopy. Due to the linewidth limitations of the pulsed laser, this detection method can only resolve vibrational structures. A cw laser induced ion depletion spectroscopy technique has been developed in order to obtain rotational resolution. Using this ion depletion method, we have studied a possible stimulated Raman transfer scheme via the 3 1Σ+ state. To this end, we have obtained all the spectroscopic information required to produce deeply bound KRb molecules in a single vibrational and rotational level. ^ Several other spectroscopic studies using the high vibrational level ultracold molecules are also discussed. ^

•Jan 1, 2007•0 citations

Spectroscopy of39K85Rb triplet excited states using ultracold a3Σ+state molecules formed by photoassociation

J T Kim, Dajun Wang, Edward E. Eyler +2 more

Convenient state-selective detection methods are proposed for exploring triplet Rydberg states from the metastable a 3 Σ + state of ultracold KRb molecules by resonance-enhanced two-photon ionization and time-of-flight (TOF) mass spectroscopy. This would allow the first accurate determination of the ionization potential. Particularly suitable resonant intermediate states include the 2 3 Π Ω , 3 3 Σ + and 4 3 Σ + states, and we report spectroscopic studies of these states. For the 2 3 Π Ω state, the spin–orbit components (Ω = 0 + , 0 − , 1 and 2) have been investigated and a shallow long-range state (5(0 + )) at ∼ 9.3 Å has been observed. We compare our observations of these three states with predictions based on ab initio potential energy curves. Such studies may also permit the direct observation of autoionizing resonances leading to efficient formation of low-lying rovibrational levels of the 2 Σ + ground state of KRb + , ideally in the v + = 0, N + = 0 level.

New Journal of Physics•May 14, 2009•27 citations
We have studied resonance-enhanced two-photon ionization of ultracold 39 K 85 Rb molecules in highly excited long-range vibrational levels of the X 1 Σ + and a 3 Σ + states. These molecules are formed by photoassociation (PA) of ultracold 39 K and 85 Rb atoms, followed by spontaneous emission to the X 1 Σ + and a 3 Σ + states. In the range 15 500–17 200 cm −1 , we observe many intermediate and long-range levels of the previously unobserved 4 3 Σ + and 4 1 Σ + states and evidence for the onset of the previously unobserved 3 3 Π state. The observed vibrational spectra of these states are in very good agreement with calculated vibrational levels based on the ab initio potentials of Rousseau, Allouche and Aubert-Frécon. Such experiments illustrate some of the unique advantages of using PA-produced ultracold molecules for investigation of long-range vibrational levels and long-range forces, and for unravelling dense spectra because only a few rotational levels are populated.
We report on the state-selective detection of near-dissociation ultracold KRb molecules in the ground $X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}^{+}$ state and the metastable $a\phantom{\rule{0.2em}{0ex}}^{3}\ensuremath{\Sigma}^{+}$ state. The molecules are produced by photoassociation of ultracold atoms followed by radiative decay into high vibrational levels of the XXX and aaa states. Detection utilizes resonance-enhanced one-color two-photon ionization, followed by time-of-flight mass spectroscopy. Scanning the detection laser frequency over the range 582−−625nm582--625\phantom{\rule{0.3em}{0ex}}\mathrm{nm}582−−625nm, we observe transitions from the ${v}^{\ensuremath{''}}=86--92$ levels of the XXX state, which are bound by up to $30\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$, and the ${v}^{\ensuremath{''}}=17--23$ levels of the aaa state, which are also bound by up to $30\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$. The measured vibrational spacings are in excellent agreement with those previously measured and those calculated from the relevant potential curves. Relative vibrational populations are also consistent with Franck-Condon factors for decay from the photoassociated levels.
We report new results on the spectroscopy of the 3 (3)Σ(+) electronic state of (39)K(85)Rb. The observations are based on resonance-enhanced multiphoton ionization of ultracold KRb molecules starting in vibrational levels v'' = 18-23 of the a (3)Σ(+) state and ionized via the intermediate 3 (3)Σ(+) state. The a-state ultracold molecules are formed by photoassociation of ultracold (39)K and (85)Rb atoms to the 3(0(+)) state of KRb followed by spontaneous emission. We discuss the potential applications of this state to future experiments, as a pathway for populating the lowest vibrational levels of the a state as well as the X state.
By using a combination of molecular beam (MB) excitation spectra and two distinct ultracold molecule excitation spectra (UM+ and UM-), we have assigned high vibrational levels of the A and 3 (1)Σ(+) states from absorption spectra of the mutually strongly perturbed A (1)Σ(+) - 3 (1)Σ(+) - 1 (1)Π - 2 (3)Σ(+) - b (3)Π states of ultracold (39)K(85)Rb molecules in the energy region between 15,116 and 16,225 cm(-1) above the minimum of the ground X (1)Σ(+) state. The ultracold molecules (UM+ and UM-) are formed by radiative decay following photoassociation (PA) to a specific level of the 3(0(+)) state (UM+) or to a specific level of the 3(0(-)) state (UM-). We observe that the A and 3 (1)Σ(+) states are observable in the UM+ spectra, but absent from the UM- spectra. This is explained by considering Hund's case (c) selection rules and transition dipole moments between the upper excited A (1)Σ(+) (2(0(+))) state and the three Ω components (0(+), 0(-), and 1) at the ground-state dissociation limit. We propose further investigations of the extended potential wells of the A and 3 (1)Σ(+) states by combining short-range MB excitation spectra in a narrow Franck-Condon (FC) window near R(e) of the X (1)Σ(+) state, and long-range UM (and PA) excitation spectra, which have much larger FC windows.
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.
This thesis describes the spectroscopy work on ultracold 39K 85Rb molecules as part of our effort towards producing ground-state ultracold polar molecules. ^ The starting points of our experiment are laser cooled and trapped K and Rb atoms in dual-species MOTs and the molecule formation method is photoassociation (PA). A fraction of the PA-produced excited-state molecules can spontaneously emit to the two lowest electronic states, the X 1Σ + state and the a 3Σ + state, to form high vibrational level molecules. In order to develop a population transfer scheme to make deeply bound molecules, we have studied the spectroscopy of KRb in several steps. Besides the PA step, we have also carried out a state-selective detection experiment to study the population distribution of the high vibrational level molecules formed via spontaneous emission. The detection method is pulsed-laser based ion time-of-flight mass spectroscopy. Due to the linewidth limitations of the pulsed laser, this detection method can only resolve vibrational structures. A cw laser induced ion depletion spectroscopy technique has been developed in order to obtain rotational resolution. Using this ion depletion method, we have studied a possible stimulated Raman transfer scheme via the 3 1Σ+ state. To this end, we have obtained all the spectroscopic information required to produce deeply bound KRb molecules in a single vibrational and rotational level. ^ Several other spectroscopic studies using the high vibrational level ultracold molecules are also discussed. ^
Convenient state-selective detection methods are proposed for exploring triplet Rydberg states from the metastable a 3 Σ + state of ultracold KRb molecules by resonance-enhanced two-photon ionization and time-of-flight (TOF) mass spectroscopy. This would allow the first accurate determination of the ionization potential. Particularly suitable resonant intermediate states include the 2 3 Π Ω , 3 3 Σ + and 4 3 Σ + states, and we report spectroscopic studies of these states. For the 2 3 Π Ω state, the spin–orbit components (Ω = 0 + , 0 − , 1 and 2) have been investigated and a shallow long-range state (5(0 + )) at ∼ 9.3 Å has been observed. We compare our observations of these three states with predictions based on ab initio potential energy curves. Such studies may also permit the direct observation of autoionizing resonances leading to efficient formation of low-lying rovibrational levels of the 2 Σ + ground state of KRb + , ideally in the v + = 0, N + = 0 level.