Europhysics Letters (EPL)

Thermal-Energy Pooling Collisions in Cesium Vapour: Cs(6 P 3/2 ) + Cs(6 P 3/2 ) → Cs(7 P 3/2, 1/2 ) + Cs(6 S 1/2 )

Slobodan Milošević, F. De Tomasi, F. Fuso, M. Allegrini

Published Dec 20, 1995• 10 citations

Abstract

We report the observation at thermal energies of the energy pooling collisions 6 P + 6 P in Cs vapour excited by a laser diode. The rate coefficients of the process Cs(6 P 3/2 ) + Cs(6 P 3/2 ) → Cs(7 P 3/2, 1/2 ) + Cs(6 S 1/2 ) are measured for the first time.

DOI: 10.1209/0295-5075/32/9/001

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Energy-pooling collisions in cesium: 6 PJ +6 PJ →6S+(nl=7P,6D,8S,4F)

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Experimental Study of Caesium 6PJ+ 6PJ -->7PJ? + 6S energy pooling collisions and modeling of the excited atom density in the presence of optical pumping and radiation trapping | NIST

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Europhysics Letters (EPL)

Thermal-Energy Pooling Collisions in Cesium Vapour: Cs(6 P 3/2 ) + Cs(6 P 3/2 ) → Cs(7 P 3/2, 1/2 ) + Cs(6 S 1/2 )

Slobodan Milošević, F. De Tomasi, F. Fuso, M. Allegrini

Published Dec 20, 1995• 10 citations

Publisher

Abstract

DOI: 10.1209/0295-5075/32/9/001

Related papers

Collision induced fluorescence in Cs vapor excited by a laser diode

M. Allegrini, F. De Tomasi, Slobodan Milošević +1 more

AIP conference proceedingsJan 1, 19933 citations

Three-body collisions in cesium vapour in the presence of buffer gas

Yifan Shen

An experimental study of energy transfer collisions, Cs(6P)+Cs(6S)+He→Cs(5D) + Cs(6S)+He, at thermal energies, was carried out in a cell. Atoms were excited to the 6P3/2 state using a single-mode diode laser. The Cs(6P) atom density and spatial distribution were mapped by monitoring the absorption of a counter-propagating laser beam. The buffer gas enhanced the energy transfer between Cs(6P) and Cs(6S), which was based on the measurement of the fluorescence from the 7D state populated by the Cs(6P)/Cs(5D) collisions. Since the 5D→6P fluorescence(3.0-3.6μm) can not be detected with this experiment, the rate coefficient has been measured relative to the known rate coefficient of the collision (i.e., 6P+5D→6S+7D). The three-body collision rate coefficient [k3 = (2.2±1.1)×10-28cm6s-1] is obtained.An experimental study of energy transfer collisions, Cs(6P)+Cs(6S)+He→Cs(5D) + Cs(6S)+He, at thermal energies, was carried out in a cell. Atoms were excited to the 6P3/2 state using a single-mode diode laser. The Cs(6P) atom density and spatial distribution were mapped by monitoring the absorption of a counter-propagating laser beam. The buffer gas enhanced the energy transfer between Cs(6P) and Cs(6S), which was based on the measurement of the fluorescence from the 7D state populated by the Cs(6P)/Cs(5D) collisions. Since the 5D→6P fluorescence(3.0-3.6μm) can not be detected with this experiment, the rate coefficient has been measured relative to the known rate coefficient of the collision (i.e., 6P+5D→6S+7D). The three-body collision rate coefficient [k3 = (2.2±1.1)×10-28cm6s-1] is obtained.

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Energy pooling collisions in cesium vapour and excitation transfer between the 6P_(3/2) and 6P_(1/2) levels

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Chinese journal of atomic and molecular physicsJan 1, 20050 citations

Three-body collisions in cesium vapour in the presence of buffer gas

Gang Zhang

An experimental study of energy transfer collisions,Cs(6P3/2)+ Cs(6P3/2)+He→Cs(4FJ)+Cs(6S1/2)+He,in the range 337 K to 357 K,has carried out in a cell.Atoms were excited to the 6P3/2 state using a single-mode diode laser.The Cs(6P3/2) atom density and spatial distribution were mapped by monitoring the absorbion of a counterpropagating laser beam.The buffer gas enhanced the energy transfer between two 6P3/2,which was based on the measurement of the fluorescence from the 4FJ states populated by three-body collision.The three-body collision rate coefficients(in units of 10-27 cm6s-1) for 4F5/2 and 4F7/2 are 1.35±0.18,2.22±0.21,respectively.An experimental study of energy transfer collisions,Cs(6P3/2)+ Cs(6P3/2)+He→Cs(4FJ)+Cs(6S1/2)+He,in the range 337 K to 357 K,has carried out in a cell.Atoms were excited to the 6P3/2 state using a single-mode diode laser.The Cs(6P3/2) atom density and spatial distribution were mapped by monitoring the absorbion of a counterpropagating laser beam.The buffer gas enhanced the energy transfer between two 6P3/2,which was based on the measurement of the fluorescence from the 4FJ states populated by three-body collision.The three-body collision rate coefficients(in units of 10-27 cm6s-1) for 4F5/2 and 4F7/2 are 1.35±0.18,2.22±0.21,respectively.

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Energy-pooling collisions in cesium: 6 PJ +6 PJ →6S+(nl=7P,6D,8S,4F)

Z. J. Jabbour, R. K. Namiotka, John Huennekens +3 more

We report experimental rate coefficients for the energy-pooling collisions Cs(6 ${\mathit{P}}_{1/2}$ )+Cs(6 ${\mathit{P}}_{1/2}$ )\ensuremath{\rightarrow}Cs(6 ${\mathit{S}}_{1/2}$ )+Cs(${\mathit{nl}}_{\mathit{J}\ensuremath{'}}$) and Cs(6 ${\mathit{P}}_{3/2}$ )+Cs(6 ${\mathit{P}}_{3/2}$ )\ensuremath{\rightarrow}Cs(6 ${\mathit{S}}_{1/2}$ )+Cs(${\mathit{nl}}_{\mathit{J}\ensuremath{'}}$) where ${\mathit{nl}}_{\mathit{J}\ensuremath{'}}$=7 ${\mathit{P}}_{1/2}$ , 7 ${\mathit{P}}_{3/2}$ , 6 ${\mathit{D}}_{3/2}$ , 6 ${\mathit{D}}_{5/2}$ , 8 ${\mathit{S}}_{1/2}$ , 4 ${\mathit{F}}_{5/2}$ , or 4 ${\mathit{F}}_{7/2}$ . Atoms were excited to either the 6 ${\mathit{P}}_{1/2}$ or 6 ${\mathit{P}}_{3/2}$ state using a single-mode Ti:sapphire laser. The excited-atom density and spatial distribution were mapped by monitoring the absorption of a counterpropagating single-mode ring dye laser beam, tuned to either the 6 ${\mathit{P}}_{1/2}$ \ensuremath{\rightarrow}8 ${\mathit{S}}_{1/2}$ or 6 ${\mathit{P}}_{3/2}$ \ensuremath{\rightarrow}7 ${\mathit{D}}_{3/2,5/2}$ transitions, which could be translated parallel to the pump beam. Transmission factors, which describe the average probability that photons emitted within the fluorescence detection region can pass through the optically thick vapor without being absorbed, were calculated for all relevant transitions. Effective lifetimes of levels populated by energy-pooling collisions are modified by radiation trapping, and these factors were calculated using the Molisch theory. These calculated quantities have been combined with the measured excited-atom densities and fluorescence ratios to yield absolute energy-pooling rate coefficients. It was found that the rate for production, in all cases, is greatest for 6D, but that 1/2-1/2 collisions are significantly more efficient than 3/2-3/2 collisions for populating 7P. It was also found that 7 ${\mathit{P}}_{1/2}$ is populated two to three times more efficiently than 7 ${\mathit{P}}_{3/2}$ in 1/2-1/2 collisions, but that the 7P fine-structure levels are approximately equally populated in 3/2-3/2 collisions. \textcopyright{} 1996 The American Physical Society.We report experimental rate coefficients for the energy-pooling collisions Cs(6${\mathit{P}}_{1/2}$)+Cs(6${\mathit{P}}_{1/2}$)\ensuremath{\rightarrow}Cs(6${\mathit{S}}_{1/2}$)+Cs(${\mathit{nl}}_{\mathit{J}\ensuremath{'}}$) and Cs(6${\mathit{P}}_{3/2}$)+Cs(6${\mathit{P}}_{3/2}$)\ensuremath{\rightarrow}Cs(6${\mathit{S}}_{1/2}$)+Cs(${\mathit{nl}}_{\mathit{J}\ensuremath{'}}$) where ${\mathit{nl}}_{\mathit{J}\ensuremath{'}}$=7${\mathit{P}}_{1/2}$, 7${\mathit{P}}_{3/2}$, 6${\mathit{D}}_{3/2}$, 6${\mathit{D}}_{5/2}$, 8${\mathit{S}}_{1/2}$, 4${\mathit{F}}_{5/2}$, or 4${\mathit{F}}_{7/2}$. Atoms were excited to either the 6${\mathit{P}}_{1/2}$ or 6${\mathit{P}}_{3/2}$ state using a single-mode Ti:sapphire laser. The excited-atom density and spatial distribution were mapped by monitoring the absorption of a counterpropagating single-mode ring dye laser beam, tuned to either the 6${\mathit{P}}_{1/2}$\ensuremath{\rightarrow}8${\mathit{S}}_{1/2}$ or 6${\mathit{P}}_{3/2}$\ensuremath{\rightarrow}7${\mathit{D}}_{3/2,5/2}$ transitions, which could be translated parallel to the pump beam. Transmission factors, which describe the average probability that photons emitted within the fluorescence detection region can pass through the optically thick vapor without being absorbed, were calculated for all relevant transitions. Effective lifetimes of levels populated by energy-pooling collisions are modified by radiation trapping, and these factors were calculated using the Molisch theory. These calculated quantities have been combined with the measured excited-atom densities and fluorescence ratios to yield absolute energy-pooling rate coefficients. It was found that the rate for production, in all cases, is greatest for 6D, but that 1/2-1/2 collisions are significantly more efficient than 3/2-3/2 collisions for populating 7P. It was also found that 7${\mathit{P}}_{1/2}$ is populated two to three times more efficiently than 7${\mathit{P}}_{3/2}$ in 1/2-1/2 collisions, but that the 7P fine-structure levels are approximately equally populated in 3/2-3/2 collisions. \textcopyright{} 1996 The American Physical Society.

Physical Review AAug 1, 199663 citations

Experimental Study of Caesium 6PJ+ 6PJ -->7PJ? + 6S energy pooling collisions and modeling of the excited atom density in the presence of optical pumping and radiation trapping | NIST

F. De Tomasi, John Huennekens, Zeina J. Kubarych +4 more

An experimental study of caesium energy pooling collisions, Cs(6PJ ) + Cs(6PJ ) ! Cs(7PJ0 ) + Cs(6S1=2), at thermal energies, has been carried out in a capillary cell using diode laser excitation. Use of the capillary cell minimizes the effects of radiation trapping, but nonetheless, such effects still play a significant role in the analysis. Consequently, a rate equation model, which treats simultaneous effects of saturation, optical pumping, and radiation trapping, has been developed and is used to determine the Cs(6PJ ) atom density under these experimental conditions. The excited atom densities are combined with measured fluorescence ratios to determine rate coefficients for the caesium energy pooling process. Our values for these rate coefficients are in agreement, within combined error bars, with values we have recently obtained under very different experimental conditions.An experimental study of caesium energy pooling collisions, Cs(6PJ ) + Cs(6PJ ) ! Cs(7PJ0 ) + Cs(6S1=2), at thermal energies, has been carried out in a capillary cell using diode laser excitation. Use of the capillary cell minimizes the effects of radiation trapping, but nonetheless, such effects still play a significant role in the analysis. Consequently, a rate equation model, which treats simultaneous effects of saturation, optical pumping, and radiation trapping, has been developed and is used to determine the Cs(6PJ ) atom density under these experimental conditions. The excited atom densities are combined with measured fluorescence ratios to determine rate coefficients for the caesium energy pooling process. Our values for these rate coefficients are in agreement, within combined error bars, with values we have recently obtained under very different experimental conditions.

Journal of Physics B Atomic Molecular and Optical PhysicsJul 5, 19972 citations

We report experimental rate coefficients for the energy-pooling collisions Cs(6

{\mathit{P}}_{1/2}

)+Cs(6

{\mathit{P}}_{1/2}

)\ensuremath{\rightarrow}Cs(6

{\mathit{S}}_{1/2}

)+Cs(${\mathit{nl}}_{\mathit{J}\ensuremath{'}}$) and Cs(6

{\mathit{P}}_{3/2}

)+Cs(6

{\mathit{P}}_{3/2}

)\ensuremath{\rightarrow}Cs(6

{\mathit{S}}_{1/2}

)+Cs(${\mathit{nl}}_{\mathit{J}\ensuremath{'}}$) where ${\mathit{nl}}_{\mathit{J}\ensuremath{'}}$=7

{\mathit{P}}_{1/2}

, 7

{\mathit{P}}_{3/2}

, 6

{\mathit{D}}_{3/2}

, 6

{\mathit{D}}_{5/2}

, 8

{\mathit{S}}_{1/2}

, 4

{\mathit{F}}_{5/2}

, or 4

{\mathit{F}}_{7/2}

. Atoms were excited to either the 6

{\mathit{P}}_{1/2}

or 6

{\mathit{P}}_{3/2}

state using a single-mode Ti:sapphire laser. The excited-atom density and spatial distribution were mapped by monitoring the absorption of a counterpropagating single-mode ring dye laser beam, tuned to either the 6

{\mathit{P}}_{1/2}

\ensuremath{\rightarrow}8

{\mathit{S}}_{1/2}

or 6

{\mathit{P}}_{3/2}

\ensuremath{\rightarrow}7

{\mathit{D}}_{3/2,5/2}

transitions, which could be translated parallel to the pump beam. Transmission factors, which describe the average probability that photons emitted within the fluorescence detection region can pass through the optically thick vapor without being absorbed, were calculated for all relevant transitions. Effective lifetimes of levels populated by energy-pooling collisions are modified by radiation trapping, and these factors were calculated using the Molisch theory. These calculated quantities have been combined with the measured excited-atom densities and fluorescence ratios to yield absolute energy-pooling rate coefficients. It was found that the rate for production, in all cases, is greatest for 6D, but that 1/2-1/2 collisions are significantly more efficient than 3/2-3/2 collisions for populating 7P. It was also found that 7

{\mathit{P}}_{1/2}

is populated two to three times more efficiently than 7

{\mathit{P}}_{3/2}

in 1/2-1/2 collisions, but that the 7P fine-structure levels are approximately equally populated in 3/2-3/2 collisions. \textcopyright{} 1996 The American Physical Society.