The transition dipole moments(TDMs) of ultracold85 Rb133 Cs molecules between the lowest vibrational ground level, (X^1Σ~+( v= 0, J= 1), and the two excited rovibrational levels, 2~3Π0+(v′= 10, J′= 2) and...The transition dipole moments(TDMs) of ultracold85 Rb133 Cs molecules between the lowest vibrational ground level, (X^1Σ~+( v= 0, J= 1), and the two excited rovibrational levels, 2~3Π0+(v′= 10, J′= 2) and 2~1Π1(v′= 22,J′= 2), are measured using depletion spectroscopy. The ground-state85 Rb133 Cs molecules are formed from cold mixed component atoms via the 2~3Π0-( v= 11, J= 0) short-range level, then detected by time-of-flight mass spectrum. A home-made external-cavity diode laser is used as the depletion laser to couple the ground level and the two excited levels. Based on the depletion spectroscopy, the corresponding TDMs are then derived to be 3.5(2)×10^(-3)eαα and 1.6(1)×10^(-2)eαα, respectively, where 0)(60 represents the atomic unit of electric dipole moment. The enhance of TDM with nearly a factor of 5 for the 21Π1(v′= 22, J′= 2) excited level means that it has stronger coupling with the ground level. It is meaningful to find more levels with much more strong coupling strength by the represented depletion spectroscopy to realize direct stimulated Raman adiabatic passage transfer from scattering atomic states to deeply molecular states.展开更多
This paper presents calculation results for the photoassociation of a NaK molecule with a two-color modulated laser and gives a detailed analysis about them.For the two-step photoassociation process in intense fields,...This paper presents calculation results for the photoassociation of a NaK molecule with a two-color modulated laser and gives a detailed analysis about them.For the two-step photoassociation process in intense fields,the effect of two-color modulated laser parameters,such as relative phase,envelope period,and laser intensity,on the population of the molecular electronic state can be obtained by solving the time-dependent Schrodinger equation through the quantum wave packet method.The numerical simulation shows not only that the influence of laser parameters on the vibrational distribution presents some regularity,but also that a higher population in the ground electronic state can be realized through adjusting these laser parameters.展开更多
We demonstrate theoretically that photoassociated molecules can be stabilized to deeply bound states. This process is achieved by transferring the population from the outer well to the inner well using the optimal con...We demonstrate theoretically that photoassociated molecules can be stabilized to deeply bound states. This process is achieved by transferring the population from the outer well to the inner well using the optimal control theory, the Cs2 molecule is taken as an example. Numerical calculations show that weakly bound molecules formed in the outer well by a pump pulse can be compressed to the inner well via a vibrational level of the ground electronic state as an intermediary by an additionally optimized laser pulse. The positively chirped pulse can enhance the population of the target state. With a transform-limited dump pulse, nearly all the photoassociated molecules in the inner well of the excited electronic state can be transferred to the deeply vibrational level of the ground electronic state.展开更多
We study the influence of external magnetic field on the shift of the resonant frequency in the photoassociation of ultracold Cs atoms, which are captured in a magnetically levitated optical crossed dipole trap. With ...We study the influence of external magnetic field on the shift of the resonant frequency in the photoassociation of ultracold Cs atoms, which are captured in a magnetically levitated optical crossed dipole trap. With the increase of the photoassociation laser intensity, the linear variation of the frequency shift is measured by recording the photoassociation spectra of the long-range 0_u^+ state of Cs molecule below the 6S_(1/2)+ 6P_(1/2) dissociation limit at different magnetic fields.The slope of the frequency shift to the intensity of the photoassociation laser exhibits a strong dependence on the external magnetic field. The experimental data is simulated with an analytic theory model, in which a single channel rectangular potential with the tunable well depth is introduced to acquire the influence of the magnetic field on the atomic behavior in the effective range where photoassociation occurs.展开更多
We report on the observation of ultracold ground electric-state cesium molecules produced directly in a magneto-optical trap with a good signal-to-noise ratio. These molecules arise from the photoassociation of magnet...We report on the observation of ultracold ground electric-state cesium molecules produced directly in a magneto-optical trap with a good signal-to-noise ratio. These molecules arise from the photoassociation of magneto-optical trap lasers and they are detected by resonantly enhanced multiphoton ionization technology. The production rate of ultracold cesium molecules is up to 4× 10^4 s-1. We measure the characteristic time of the ground electric-state cesium molecules generated in the experiment and investigate the Cs2+ molecular ion intensity as a function of the trapping laser intensity and the ionization pulse laser energy. We conclude that the production of cold cesium molecules may be enhanced by using appropriate experimental parameters, which is useful for future experiments involving the production and trapping of ultracold ground electric-state molecules.展开更多
The photoassociation dynamics of ultracold lithium atoms controlled by a cut-off pulse has been investigated theoretically by solving numerically the time-dependent Schr6dinger equation using the mapped Fourier grid m...The photoassociation dynamics of ultracold lithium atoms controlled by a cut-off pulse has been investigated theoretically by solving numerically the time-dependent Schr6dinger equation using the mapped Fourier grid method. The frequency components of the laser pulse close to the atomic resonance are partly cut off. Compared with the typical Gauss-type pulses, the cut-off pulse is helpful to suppress efficiently the weakly bound states and prepare the associated molecules in the lower vibrational states. Especially, the dependence of photoassociation probability on the cut-off position of the laser pulse is explored.展开更多
High-resolution photoassociation spectroscopy is reported using a modulation spectroscopy technology in a cesium atomic magneto-optical trap. The two lowest vibrational levels have been experimentally observed which h...High-resolution photoassociation spectroscopy is reported using a modulation spectroscopy technology in a cesium atomic magneto-optical trap. The two lowest vibrational levels have been experimentally observed which have been theo- retically predicted in [Phys. Rev. A 75 052501 (2007)]. A new potential curve is obtained by using the Rydberg-Klein-Ress method with a well depth of -82,384 + 0,026 cm-1, which is deeper than the result of previous experiment (-77.909 cm-1) and the theoretical prediction (-81.6445 cm- l ).展开更多
We report a method of high-sensitively detecting the weak signal in photoassociation (PA) spectra of ultracold NaCs molecules by phase sensitive-demodulated trap-loss spectra of Na atoms from a photomultiplier tube....We report a method of high-sensitively detecting the weak signal in photoassociation (PA) spectra of ultracold NaCs molecules by phase sensitive-demodulated trap-loss spectra of Na atoms from a photomultiplier tube. We find that the signal-to-noise ratio (SNR) of the PA spectra is strongly dependent on the integration time and the sensitivity of the lock-in amplifier, and our results show reasonable agreement with the theoretical analyses of the SNR with the demodulation parameters. Meanwhile, we investigate the effect of the interaction time of the PA laser with the colliding Na-Cs atom pairs on the SNR of the PA spectra. The atom loss rate is dependent on both the PA-induced atom loss and the loading of the MOT. The high-sensitive detection of the excited ultracold NaCs molecules lays a solid foundation for further study of the formation and application of ultracold NaCs molecules.展开更多
Reanalysis of the photoassociation spectrum of the weakly binding (6S1/2 + 6P3/2) lg 133Cs2 levels, reported in the previous study [J. Mol. Spectro. 255 (2009) 106], is performed by using a Lu-Fano graph coupled ...Reanalysis of the photoassociation spectrum of the weakly binding (6S1/2 + 6P3/2) lg 133Cs2 levels, reported in the previous study [J. Mol. Spectro. 255 (2009) 106], is performed by using a Lu-Fano graph coupled to the improved LeRoy- Bernstein formula including two additional modified terms. A more accurate coefficient (c3) is obtained for the leading long-range potential (-c3/R3) of a diatomic molecule.展开更多
We present high resolution photoassociation spectroscopy of ultracold 23Na133Cs molecules in a long-range c3∑+ state below the (3S1/2 + 6P3/2) asymptote. We perform photoassociation spectroscopy in a dual-species...We present high resolution photoassociation spectroscopy of ultracold 23Na133Cs molecules in a long-range c3∑+ state below the (3S1/2 + 6P3/2) asymptote. We perform photoassociation spectroscopy in a dual-species magneto-optical trap (MOT) and detect the photoassociation resonances using trap-loss spectroscopy. By fitting the experimental data with the semi-classical LeRoy-Bernstein formula, we deduce the long-range molecular coefficient C6 and derive the empirical potential energy curve in the long-range region.展开更多
In this paper, ultracold cesium molecules are formed through photoassociation technology, which is carried out in a magneto-optical trap. High resolution photoassociaion spectra with the rotational progressions up to ...In this paper, ultracold cesium molecules are formed through photoassociation technology, which is carried out in a magneto-optical trap. High resolution photoassociaion spectra with the rotational progressions up to J = 7 are obtained. Three rovibrational levels of the long-range 0+ state of Cs2 below the (6S1/2 + 6P1/2) dissociation limit are specifically investigated. By fitting their binding energy intervals to the non-rigid rotational model, the rotational constant of the long- range 0u+ state is determined. A proportional dependence of the value of the rotational constant on the vibrational quantum number is demonstrated.展开更多
The high-resolution photoassociation spectrum of the ultracold cesium molecular 0+ state below the 6S1/2 + 6PI/2 limit is presented in this paper. The saturation of the photoassociation scattering probability is obs...The high-resolution photoassociation spectrum of the ultracold cesium molecular 0+ state below the 6S1/2 + 6PI/2 limit is presented in this paper. The saturation of the photoassociation scattering probability is observed from the depen dence of the trap-loss probability on the photoassociation laser intensity. The corresponding resonant line width is also demonstrated to increase linearly with increasing photoassociation laser intensity. Our experimental data have good con sistency with the theoretical saturation model of Bohn and Julienne [Bohn J L and Julienne P S 1999 Phys. Rev. A 60 1].展开更多
We investigate the high resolution photoassociation spectra of ^(85)Rb_2 molecules in 0~+_u long range state below the(5S_(1/2)+ 5P_(1/2)) asymptote. The ^(85)Rb atomic samples are trapped in a dark magnet...We investigate the high resolution photoassociation spectra of ^(85)Rb_2 molecules in 0~+_u long range state below the(5S_(1/2)+ 5P_(1/2)) asymptote. The ^(85)Rb atomic samples are trapped in a dark magneto–optical trap(MOT) and prepared in the dark state. With the help of trap loss technique, we obtain considerable photoassociation spectroscopy with rovibrational resolution, some of which have never been observed before. The observed spectrum is fitted by a rigid rotation model, and the rotational constants of ultracold ^(85)Rb_2 molecule in long range 0~+_u are obtained for different vibrational states. By applying the Le Roy–Bernstein method, we assign the vibrational quantum numbers and derive C_3 coefficient, which is used to obtain the potential energy curve.展开更多
We report an effective method for enhancing the photoassociation of ultracold atoms using a non-resonant magnetic field,which enables the manipulation of the coupling between the wavefunctions of the colliding atomic ...We report an effective method for enhancing the photoassociation of ultracold atoms using a non-resonant magnetic field,which enables the manipulation of the coupling between the wavefunctions of the colliding atomic pairs and the excited molecules.A series of photoassociation spectra are measured for different magnetic fields.We show that the photoassociation rate is significantly dependent on the non-resonant magnetic field.A qualitatively theoretical explanation is provided,and shows a good agreement with the experimental result.展开更多
The laser-induced vibrational state-selectivity of product HF in photoassociation reaction H+F→HF is theoret- ically investigated by using the time-dependent quantum wave packet method. The population transfer proce...The laser-induced vibrational state-selectivity of product HF in photoassociation reaction H+F→HF is theoret- ically investigated by using the time-dependent quantum wave packet method. The population transfer process from the continuum state down to the bound vibrational states can be controlled by the driving laser. The effects of laser pulse parameters and the initial momentum of the two collision atoms on the vibrational population of the product HF are discussed in detail. Photodissociation accompanied with the photoassociation process is also described.展开更多
Ultracold polar RbCs molecules are produced via photoassociation in a laser-cooled mixture of ^85Rb and ^133Cs atoms. The a3∑+ state molecules which decay from electronically excited (2)0- state RbCs molecules are...Ultracold polar RbCs molecules are produced via photoassociation in a laser-cooled mixture of ^85Rb and ^133Cs atoms. The a3∑+ state molecules which decay from electronically excited (2)0- state RbCs molecules are detected by resonance- enhanced two-photon ionization. The new rovibrational levels (v = 189, 190) in the (2)0- state are also observed, which exist in theory and have not been observed in experiments yet. The corresponding rotational constants are measured by photoassociation spectroscopy, which are consistent with theoretical calculations using a nonrigid rotor model.展开更多
We report on the observation of enhanced high-order partial wave scattering from atom atom interaction via changing the temperature of a magneto optical trap in the process of photoassociation. The high-order scatteri...We report on the observation of enhanced high-order partial wave scattering from atom atom interaction via changing the temperature of a magneto optical trap in the process of photoassociation. The high-order scattering partial wave is directly manifested through the large signal amplitude of the rovibrational resonance levels of trap-loss spectroscopy from photoassociation.展开更多
In this paper, ultracold atoms and molecules in a dark magneto-optical trap (MOT) are studied via depumping the cesium cold atoms into the dark hyperfine ground state. The collision rate is reduced to 0.45 s-1 and t...In this paper, ultracold atoms and molecules in a dark magneto-optical trap (MOT) are studied via depumping the cesium cold atoms into the dark hyperfine ground state. The collision rate is reduced to 0.45 s-1 and the density of the atoms is increased to 5.6 × 1011 cm-3 when the fractional population of the atoms in the bright hyperfine ground state is as low as 0.15. The vibrational spectra of the ultracold cesium molecules are also studied in a standard MOT and in a dark MOT separately. The experimental results are analyzed by using the perturbative quantum approach.展开更多
We investigate the production of ultracold ground state x^1∑7+(u = 0) RbCs molecules in the lowest vibrational level via short-range photoassociation followed by spontaneous emission. The starting point is the las...We investigate the production of ultracold ground state x^1∑7+(u = 0) RbCs molecules in the lowest vibrational level via short-range photoassociation followed by spontaneous emission. The starting point is the laser cooled 85Rb and laa cs atoms in a dual species, forced dark magneto-optical trap. The special intermediate level (5)O+ (u = 10) correlated to the (2)311 electric state is achieved by the photoassociation process. The formed ground state X1∑+ (u = 0) molecule is resonantly excited to the 2111 intermediate state by a 651 nm pulse laser and is ionized by a 532nm 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 85Rblaacs molecules is facilitative for the further research about the manipulation of ultracold molecules in the rovibrational ground state.展开更多
We investigate the two-step association process of NaCs using the time-dependent wave packet method.Ground state atoms can be photoassociated to the low vibrational levels of the ground state for an NaCs molecule by t...We investigate the two-step association process of NaCs using the time-dependent wave packet method.Ground state atoms can be photoassociated to the low vibrational levels of the ground state for an NaCs molecule by the two-step association.The time-dependent Schro¨dinger equation of the association process is solved within a three-state model and the wave packet is propagated with the "split operator-Fourier transform" scheme and the rotating-wave approximation(RWA).The vibrational population distribution of the ground state can be obtained by projecting the wave packet to every vibrational level of the ground state.The results not only show that for NaCs achievement of photoassociation production is accompanied by the photodissociation of the higher vibrational molecules,but also show that the vibrational distribution in lower vibrational levels of the ground state changes with the laser parameters.展开更多
基金Supported by the National Key Research and Development Program of China under Grant No 2017YFA0304203the National Natural Science Foundation of China under Grant Nos 61675120 and 11434007+3 种基金the National Natural Science Foundation of China for Excellent Research Team under Grant No 61121064the Shanxi Scholarship Council of China,the 1331KSCthe PCSIRT under Grant No IRT13076the Applied Basic Research Project of Shanxi Province under Grant No 201601D202008
文摘The transition dipole moments(TDMs) of ultracold85 Rb133 Cs molecules between the lowest vibrational ground level, (X^1Σ~+( v= 0, J= 1), and the two excited rovibrational levels, 2~3Π0+(v′= 10, J′= 2) and 2~1Π1(v′= 22,J′= 2), are measured using depletion spectroscopy. The ground-state85 Rb133 Cs molecules are formed from cold mixed component atoms via the 2~3Π0-( v= 11, J= 0) short-range level, then detected by time-of-flight mass spectrum. A home-made external-cavity diode laser is used as the depletion laser to couple the ground level and the two excited levels. Based on the depletion spectroscopy, the corresponding TDMs are then derived to be 3.5(2)×10^(-3)eαα and 1.6(1)×10^(-2)eαα, respectively, where 0)(60 represents the atomic unit of electric dipole moment. The enhance of TDM with nearly a factor of 5 for the 21Π1(v′= 22, J′= 2) excited level means that it has stronger coupling with the ground level. It is meaningful to find more levels with much more strong coupling strength by the represented depletion spectroscopy to realize direct stimulated Raman adiabatic passage transfer from scattering atomic states to deeply molecular states.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674198)the Natural Science Foundations of Shandong Province,China(Grant Nos.ZR2014AM022 and ZR2015AL023)Partial financial support from Taishan Scholar Project of Shandong Province is also acknowledged
文摘This paper presents calculation results for the photoassociation of a NaK molecule with a two-color modulated laser and gives a detailed analysis about them.For the two-step photoassociation process in intense fields,the effect of two-color modulated laser parameters,such as relative phase,envelope period,and laser intensity,on the population of the molecular electronic state can be obtained by solving the time-dependent Schrodinger equation through the quantum wave packet method.The numerical simulation shows not only that the influence of laser parameters on the vibrational distribution presents some regularity,but also that a higher population in the ground electronic state can be realized through adjusting these laser parameters.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10974024)the SRFDP, China (Grant No. 20090041110025)
文摘We demonstrate theoretically that photoassociated molecules can be stabilized to deeply bound states. This process is achieved by transferring the population from the outer well to the inner well using the optimal control theory, the Cs2 molecule is taken as an example. Numerical calculations show that weakly bound molecules formed in the outer well by a pump pulse can be compressed to the inner well via a vibrational level of the ground electronic state as an intermediary by an additionally optimized laser pulse. The positively chirped pulse can enhance the population of the target state. With a transform-limited dump pulse, nearly all the photoassociated molecules in the inner well of the excited electronic state can be transferred to the deeply vibrational level of the ground electronic state.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0304203)the Chang Jiang Scholars and Innovative Research Team in the University of the Ministry of Education of China(Grant No.IRT13076)+2 种基金the National Natural Science Foundation of China(Grant Nos.61722507,61675121,61705123,and 11434007)the Fund for Shanxi 1331 Project Key Subjects Construction,Chinathe Applied Basic Research Project of Shanxi Province,China(Grant No.201701D221002)
文摘We study the influence of external magnetic field on the shift of the resonant frequency in the photoassociation of ultracold Cs atoms, which are captured in a magnetically levitated optical crossed dipole trap. With the increase of the photoassociation laser intensity, the linear variation of the frequency shift is measured by recording the photoassociation spectra of the long-range 0_u^+ state of Cs molecule below the 6S_(1/2)+ 6P_(1/2) dissociation limit at different magnetic fields.The slope of the frequency shift to the intensity of the photoassociation laser exhibits a strong dependence on the external magnetic field. The experimental data is simulated with an analytic theory model, in which a single channel rectangular potential with the tunable well depth is introduced to acquire the influence of the magnetic field on the atomic behavior in the effective range where photoassociation occurs.
基金supported by the National Key Fundamental Basic Research Program of China (Grant No. 2006CB921603)the Major Program of National Natural Science Foundation of China (Grant No. 10934004)+3 种基金the National Natural Science Foundation of China (Grant Nos. 60978018,60808009,61008012,and 60978001)the New Teacher Fund of the Ministry of Education of China(Grant No. 200801081021)the National Natural Science Foundation of China for Excellent Research Team (Grant No. 60821004)the Natural Science Foundation of Shanxi Province of China (Grant No. 2009011059-2)
文摘We report on the observation of ultracold ground electric-state cesium molecules produced directly in a magneto-optical trap with a good signal-to-noise ratio. These molecules arise from the photoassociation of magneto-optical trap lasers and they are detected by resonantly enhanced multiphoton ionization technology. The production rate of ultracold cesium molecules is up to 4× 10^4 s-1. We measure the characteristic time of the ground electric-state cesium molecules generated in the experiment and investigate the Cs2+ molecular ion intensity as a function of the trapping laser intensity and the ionization pulse laser energy. We conclude that the production of cold cesium molecules may be enhanced by using appropriate experimental parameters, which is useful for future experiments involving the production and trapping of ultracold ground electric-state molecules.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10974024)the SRFDP, China (Grant No. 20090041110025)
文摘The photoassociation dynamics of ultracold lithium atoms controlled by a cut-off pulse has been investigated theoretically by solving numerically the time-dependent Schr6dinger equation using the mapped Fourier grid method. The frequency components of the laser pulse close to the atomic resonance are partly cut off. Compared with the typical Gauss-type pulses, the cut-off pulse is helpful to suppress efficiently the weakly bound states and prepare the associated molecules in the lower vibrational states. Especially, the dependence of photoassociation probability on the cut-off position of the laser pulse is explored.
基金Project supported by the National Basic Research Program of China (Grant No. 2012CB921603), the National High Technology Research and Development Program of China (Grant No. 2011AA010801), the National Natural Science Foundation of China (Grant Nos. 61008012 and 10934004), the International Science and Technology Corporation Program of China (Grant No. 20l I DFA12490), the New Teacher Fund of the Ministry of Education of China (Grant No. 20101401120004), and the Natural Science Foundation of Shanxi Province, China (Grant No. 2013021005-1).
文摘High-resolution photoassociation spectroscopy is reported using a modulation spectroscopy technology in a cesium atomic magneto-optical trap. The two lowest vibrational levels have been experimentally observed which have been theo- retically predicted in [Phys. Rev. A 75 052501 (2007)]. A new potential curve is obtained by using the Rydberg-Klein-Ress method with a well depth of -82,384 + 0,026 cm-1, which is deeper than the result of previous experiment (-77.909 cm-1) and the theoretical prediction (-81.6445 cm- l ).
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0304203)the Chang Jiang Scholars and Innovative Research Team in the University of the Ministry of Education of China(Grant No.IRT13076)+2 种基金the National Natural Science Foundation of China(Grant Nos.91436108,61378014,61675121,61705123,and 61722507)the Fund for Shanxi“1331 Project”Key Subjects Construction,Chinathe Foundation for Outstanding Young Scholars of Shanxi Province,China(Grant No.201601D021001)
文摘We report a method of high-sensitively detecting the weak signal in photoassociation (PA) spectra of ultracold NaCs molecules by phase sensitive-demodulated trap-loss spectra of Na atoms from a photomultiplier tube. We find that the signal-to-noise ratio (SNR) of the PA spectra is strongly dependent on the integration time and the sensitivity of the lock-in amplifier, and our results show reasonable agreement with the theoretical analyses of the SNR with the demodulation parameters. Meanwhile, we investigate the effect of the interaction time of the PA laser with the colliding Na-Cs atom pairs on the SNR of the PA spectra. The atom loss rate is dependent on both the PA-induced atom loss and the loading of the MOT. The high-sensitive detection of the excited ultracold NaCs molecules lays a solid foundation for further study of the formation and application of ultracold NaCs molecules.
基金supported by the National Basic Research Program of China(Grant No.2012CB921603)the 863 Program(Grant No.2011AA010801)+3 种基金the National Natural Science Foundation of China(Grant Nos.61008012,10934004,11074204,and 11174236)the International Science and Technology Cooperation Program of China(Grant No.2011DFA12490)the New Teacher Fund of the Ministry of Education of China(Grant No.20101401120004)the Natural Science Foundation of Shanxi Province,China(Grant No.2013021005-1)
文摘Reanalysis of the photoassociation spectrum of the weakly binding (6S1/2 + 6P3/2) lg 133Cs2 levels, reported in the previous study [J. Mol. Spectro. 255 (2009) 106], is performed by using a Lu-Fano graph coupled to the improved LeRoy- Bernstein formula including two additional modified terms. A more accurate coefficient (c3) is obtained for the leading long-range potential (-c3/R3) of a diatomic molecule.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0304203)the Chang Jiang Scholars and Innovative Research Team in the University of the Ministry of Education of China(Grant No.IRT13076)+2 种基金the National Natural Science Foundation of China(Grant Nos.91436108,61378014,61675121,61705123,and 11434007)the Fund for Shanxi“1331 Project”Key Subjects Construction,Chinathe Foundation for Outstanding Young Scholars of Shanxi Province,China(Grant No.201601D021001)
文摘We present high resolution photoassociation spectroscopy of ultracold 23Na133Cs molecules in a long-range c3∑+ state below the (3S1/2 + 6P3/2) asymptote. We perform photoassociation spectroscopy in a dual-species magneto-optical trap (MOT) and detect the photoassociation resonances using trap-loss spectroscopy. By fitting the experimental data with the semi-classical LeRoy-Bernstein formula, we deduce the long-range molecular coefficient C6 and derive the empirical potential energy curve in the long-range region.
基金supported by the National Basic Research Program of China (Grant No. 2012CB921603)the National High Technology Research and Development Program of China (Grant No. 2011AA010801)+3 种基金the National Natural Science Foundation of China (Grant Nos. 61008012 and 10934004)the International Science and Technology Cooperation Program of China (Grant No. 2001DFA12490)the Project for Excellent Research Team of the National Natural Science Foundation of China (Grant No. 61121064)the New Teacher Fund of the Ministry of Education of China (Grant No. 20101401120004)
文摘In this paper, ultracold cesium molecules are formed through photoassociation technology, which is carried out in a magneto-optical trap. High resolution photoassociaion spectra with the rotational progressions up to J = 7 are obtained. Three rovibrational levels of the long-range 0+ state of Cs2 below the (6S1/2 + 6P1/2) dissociation limit are specifically investigated. By fitting their binding energy intervals to the non-rigid rotational model, the rotational constant of the long- range 0u+ state is determined. A proportional dependence of the value of the rotational constant on the vibrational quantum number is demonstrated.
基金supported by the National Basic Research Program of China(Grant No.2012CB921603)the 863 Program(Grant No.2011AA010801)+4 种基金the National Natural Science Foundation of China(Grant Nos.61008012,10934004,60978001,60978018,and 11174187)the International Science&Technology Cooperation Program of China(Grant No.2011DFA12490)the National Natural Science Foundation of China for Excellent Research Team(Grant No.61121064)the Natural Science Foundation of Shanxi Province,China(Grant Nos.2011011004 and 2011081030)the New Teacher Fund of the Ministry of Education of China(Grant No.20101401120004)
文摘The high-resolution photoassociation spectrum of the ultracold cesium molecular 0+ state below the 6S1/2 + 6PI/2 limit is presented in this paper. The saturation of the photoassociation scattering probability is observed from the depen dence of the trap-loss probability on the photoassociation laser intensity. The corresponding resonant line width is also demonstrated to increase linearly with increasing photoassociation laser intensity. Our experimental data have good con sistency with the theoretical saturation model of Bohn and Julienne [Bohn J L and Julienne P S 1999 Phys. Rev. A 60 1].
基金supported by the National Natural Science Foundation of China(Grant Nos.61675120,11434007,and 61378015)the National Natural Science Foundation of China for Excellent Research Team(Grant No.61121064)+1 种基金the Shanxi Scholarship Council of Chinathe PCSIRT(Grant No.IRT 13076)
文摘We investigate the high resolution photoassociation spectra of ^(85)Rb_2 molecules in 0~+_u long range state below the(5S_(1/2)+ 5P_(1/2)) asymptote. The ^(85)Rb atomic samples are trapped in a dark magneto–optical trap(MOT) and prepared in the dark state. With the help of trap loss technique, we obtain considerable photoassociation spectroscopy with rovibrational resolution, some of which have never been observed before. The observed spectrum is fitted by a rigid rotation model, and the rotational constants of ultracold ^(85)Rb_2 molecule in long range 0~+_u are obtained for different vibrational states. By applying the Le Roy–Bernstein method, we assign the vibrational quantum numbers and derive C_3 coefficient, which is used to obtain the potential energy curve.
基金the National Key Research and Development Program of China(Grant No.2017YFA0304203)the National Natural Science Foundation of China(Grant Nos.61722507,61675121,and 61705123),PCSIRT,China(Grant No.IRT17R70),111 Project,China(Grant No.D18001)+2 种基金the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi(OIT),Chinathe Applied Basic Research Project of Shanxi Province,China(Grant Nos.201801D221004,201901D211191,and 201901D211188)the Shanxi 1331 KSC,and Collaborative Grant by the Russian Foundation for Basic Research and the National Natural Science Foundation of China(Grant Nos.6191101339 and 20-53-53025 in the RFBR classification)。
文摘We report an effective method for enhancing the photoassociation of ultracold atoms using a non-resonant magnetic field,which enables the manipulation of the coupling between the wavefunctions of the colliding atomic pairs and the excited molecules.A series of photoassociation spectra are measured for different magnetic fields.We show that the photoassociation rate is significantly dependent on the non-resonant magnetic field.A qualitatively theoretical explanation is provided,and shows a good agreement with the experimental result.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10674022 and 20633070).
文摘The laser-induced vibrational state-selectivity of product HF in photoassociation reaction H+F→HF is theoret- ically investigated by using the time-dependent quantum wave packet method. The population transfer process from the continuum state down to the bound vibrational states can be controlled by the driving laser. The effects of laser pulse parameters and the initial momentum of the two collision atoms on the vibrational population of the product HF are discussed in detail. Photodissociation accompanied with the photoassociation process is also described.
基金supported by the National Basic Research Program of China (Grant No. 2012CB921603)the International Science & Technology Cooperation Program of China (Grant No. 2011DFA12490)+1 种基金the National Natural Science Foundation of China (Grant Nos. 61275209, 10934004, and 11004125)the National Natural Science Foundation for Excellent Research Team, China (Grant No. 61121064)
文摘Ultracold polar RbCs molecules are produced via photoassociation in a laser-cooled mixture of ^85Rb and ^133Cs atoms. The a3∑+ state molecules which decay from electronically excited (2)0- state RbCs molecules are detected by resonance- enhanced two-photon ionization. The new rovibrational levels (v = 189, 190) in the (2)0- state are also observed, which exist in theory and have not been observed in experiments yet. The corresponding rotational constants are measured by photoassociation spectroscopy, which are consistent with theoretical calculations using a nonrigid rotor model.
基金supported by the 973 Program (Grant No. 2006CB921603)the 863 Program (Grant No. 2009AA01Z319)+3 种基金the National Natural Science Foundation of China (Grant Nos. 61008012, 11074154, 10934004, 60978018, 60978001, and 60808009)the National Natural Science Foundation of China for Excellent Research Team (Grant No. 60821004)the Natural Science Foundation of Shanxi Province of China (Grant No. 2009011059-2)the New Teacher Fund of the Ministry of Education of China (Grant No. 20101401120004)
文摘We report on the observation of enhanced high-order partial wave scattering from atom atom interaction via changing the temperature of a magneto optical trap in the process of photoassociation. The high-order scattering partial wave is directly manifested through the large signal amplitude of the rovibrational resonance levels of trap-loss spectroscopy from photoassociation.
基金Project supported by the National Basic Research Program of China (Grant No. 2012CB921603)the International Science & Technology Cooperation Program of China (Grant No. 2011DFA12490)+1 种基金the National Natural Science Foundation of China (Grant Nos.10934004,60978001,60978018,60808009,61078001,and 61008012)the Natural Science Foundation of Shanxi Province,China (Grant No. 2011011004)
文摘In this paper, ultracold atoms and molecules in a dark magneto-optical trap (MOT) are studied via depumping the cesium cold atoms into the dark hyperfine ground state. The collision rate is reduced to 0.45 s-1 and the density of the atoms is increased to 5.6 × 1011 cm-3 when the fractional population of the atoms in the bright hyperfine ground state is as low as 0.15. The vibrational spectra of the ultracold cesium molecules are also studied in a standard MOT and in a dark MOT separately. The experimental results are analyzed by using the perturbative quantum approach.
基金Supported by the National Basic Research Program of China under Grant No 2012CB921603the National Natural Science Foundation of China under Grant Nos 61275209,11304189,61378015 and 11434007+1 种基金the National Natural Science Foundation for Excellent Research Team under Grant No 61121064the Program for Changjiang Scholars and Innovative Research Team in University under Grant No IRT13076
文摘We investigate the production of ultracold ground state x^1∑7+(u = 0) RbCs molecules in the lowest vibrational level via short-range photoassociation followed by spontaneous emission. The starting point is the laser cooled 85Rb and laa cs atoms in a dual species, forced dark magneto-optical trap. The special intermediate level (5)O+ (u = 10) correlated to the (2)311 electric state is achieved by the photoassociation process. The formed ground state X1∑+ (u = 0) molecule is resonantly excited to the 2111 intermediate state by a 651 nm pulse laser and is ionized by a 532nm 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 85Rblaacs molecules is facilitative for the further research about the manipulation of ultracold molecules in the rovibrational ground state.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11074151)the National Basic Research Program of China (Grant No. 2011CB808100)
文摘We investigate the two-step association process of NaCs using the time-dependent wave packet method.Ground state atoms can be photoassociated to the low vibrational levels of the ground state for an NaCs molecule by the two-step association.The time-dependent Schro¨dinger equation of the association process is solved within a three-state model and the wave packet is propagated with the "split operator-Fourier transform" scheme and the rotating-wave approximation(RWA).The vibrational population distribution of the ground state can be obtained by projecting the wave packet to every vibrational level of the ground state.The results not only show that for NaCs achievement of photoassociation production is accompanied by the photodissociation of the higher vibrational molecules,but also show that the vibrational distribution in lower vibrational levels of the ground state changes with the laser parameters.