The Journal of Chemical Physics

Preferential population of magnetic sublevels of photodissociated atoms. I. Predissociation of Cs2

Hajime Katô, Kyoko Onomichi

Published Feb 15, 1985• 20 citations

Abstract

Preferential population of the magnetic sublevels of Cs(6p 2P3/2) atoms produced by predissociation of the C 1Πu state of the Cs2 molecule along the repulsive molecular state b 3Σ+u , has been found by observing the polarization of the atomic fluorescence Cs(6p 2Pm3/2→6s 2S1/2). By applying an external magnetic field, we have determined the population of the magnetic sublevels Cs(6p 2Pm3/2) directly from the intensities of the fluorescence lines Cs(6p 2Pm3/2 →6s 2Sm±11/2 ) split by the Zeeman effect. The results are analyzed theoretically by assuming the separability of electronic and nuclear motion for the dissociation along the repulsive potential curve. The effect of the external magnetic field on the photodissociation has been made clear, and the observed results could be fully explained on the basis of the adiabatic approximation.

DOI: 10.1063/1.448396

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The Journal of Chemical Physics

Preferential population of magnetic sublevels of photodissociated atoms. I. Predissociation of Cs2

Hajime Katô, Kyoko Onomichi

Published Feb 15, 1985• 20 citations

Publisher

Abstract

DOI: 10.1063/1.448396

Related papers

Preferential population of magnetic sublevels of photodissociated atoms. Photodissociation of alkali-metal dimers and the effect of magnetic field

Hajime Katô

By applying an external magnetic field, we have determined the population of the magnetic sublevels of photodissociated atoms from the intensities of atomic fluorescence lines split by the Zeeman effect. A preferential population of the magnetic sublevels of the atomic fragment Na(3 2P3/2), which arises from the direct photodissociation through the D1Π(continuum) state of the NaK molecule, has been observed. The results are explained by assuming the separability of electronic and nuclear motion during the dissociation. The observed results could be rationalized by the sum of the photodissociation amplitudes caused by excitation of the P, Q and R branches. The population of the magnetic sublevels of Rb(5 2P3/2) atoms produced by predissociation of the C1Πu state of the Rb2 molecule by the repulsive molecular state c3Σ+u has been determined from the Zeeman spectra of the emission Rb(5 2P3/2→ 5 2Sm′1/2). The observed results are interpreted by including the spin-orbit coupling between an excited level of the C1Πu state and levels of the c3Σ+u state and the effect of the external magnetic field.By applying an external magnetic field, we have determined the population of the magnetic sublevels of photodissociated atoms from the intensities of atomic fluorescence lines split by the Zeeman effect. A preferential population of the magnetic sublevels of the atomic fragment Na(3 2P3/2), which arises from the direct photodissociation through the D1Π(continuum) state of the NaK molecule, has been observed. The results are explained by assuming the separability of electronic and nuclear motion during the dissociation. The observed results could be rationalized by the sum of the photodissociation amplitudes caused by excitation of the P, Q and R branches. The population of the magnetic sublevels of Rb(5 2P3/2) atoms produced by predissociation of the C1Πu state of the Rb2 molecule by the repulsive molecular state c3Σ+u has been determined from the Zeeman spectra of the emission Rb(5 2P3/2→ 5 2Sm′1/2). The observed results are interpreted by including the spin-orbit coupling between an excited level of the C1Πu state and levels of the c3Σ+u state and the effect of the external magnetic field.

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m j -Resolved Doppler Spectroscopy of Cs(6p2P3/2,m j) Atoms Predissociated from a Single Level Cs2D1Σu+ (v = 46, J = 54)

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Abstract In a plane perpendicular to a magnetic field a collimated cesium beam was crossed at right angles by a pump laser beam. Cs2 molecules were excited to the D1Σu+ (v = 46, J = 54) level, which predissociated selectively to Cs(6s2S1/2) + Cs(6p2P3/2) atoms. The mj-resolved excitation spectra of the Cs(8s2S1/2,m′j ← 6p2P3/2,mj) transitions at a magnetic field of 1.91 kG were measured using a probe laser beam propagated either along the magnetic field or along the pump beam. The population of Cs(6p2P3/2,mj) atoms was found to be in the ratio 77 : 136 : 100 : 46 for mj = 3/2, 1/2, −1/2, and −3/2 based on an analysis of the line intensities. From the line shapes of the excitation spectra, Cs(6p2P3/2,±1/2) atoms were found to recoil predominantly parallel to the magnetic field H, and Cs(6p2P3/2,±3/2) atoms were found to recoil predominantly perpendicular to H.Abstract In a plane perpendicular to a magnetic field a collimated cesium beam was crossed at right angles by a pump laser beam. Cs2 molecules were excited to the D1Σu+ (v = 46, J = 54) level, which predissociated selectively to Cs(6s2S1/2) + Cs(6p2P3/2) atoms. The mj-resolved excitation spectra of the Cs(8s2S1/2,m′j ← 6p2P3/2,mj) transitions at a magnetic field of 1.91 kG were measured using a probe laser beam propagated either along the magnetic field or along the pump beam. The population of Cs(6p2P3/2,mj) atoms was found to be in the ratio 77 : 136 : 100 : 46 for mj = 3/2, 1/2, −1/2, and −3/2 based on an analysis of the line intensities. From the line shapes of the excitation spectra, Cs(6p2P3/2,±1/2) atoms were found to recoil predominantly parallel to the magnetic field H, and Cs(6p2P3/2,±3/2) atoms were found to recoil predominantly perpendicular to H.

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Translationally cold Cs[sub 2] molecules formation in a magneto-optical trap

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We report on the observation of translationally cold Cs2 molecules at temperatures in the 300–70 μK range, produced by the photoassociation of cold Cs atoms in a vapor-cell magneto-optical trap. The detection method is based on pulsed-laser photoionization of Cs2 molecules into Cs2+ ions, selectively detected through a time-of-flight mass spectrometer. This technique, together with the usual trap-loss method, enables us to perform the spectroscopy of the long-range attractive molecular states below the 6s 2S1/2+6p 2P3/2 dissociation limit.We report on the observation of translationally cold Cs2 molecules at temperatures in the 300–70 μK range, produced by the photoassociation of cold Cs atoms in a vapor-cell magneto-optical trap. The detection method is based on pulsed-laser photoionization of Cs2 molecules into Cs2+ ions, selectively detected through a time-of-flight mass spectrometer. This technique, together with the usual trap-loss method, enables us to perform the spectroscopy of the long-range attractive molecular states below the 6s 2S1/2+6p 2P3/2 dissociation limit.

AIP conference proceedingsJan 1, 19980 citations

Study of the fluorescence spectrum of cesium vapor excited by the laser of 441.6nm line

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Populations of the n 2L(nL=7p,6D)states of Cs atoms by photodissociation of Cs_2 molecules through the use of the fixed frequence line 441.6nm of a He-Cd laser radiation are produced.Combining ratios of atomic to molecular fluorescence at the Cs density range between 1 and 9×10 15 cm -3 ,the ratios of collisional excitation transfer rate coefficients and the predissociation rates are obtained.The cross section for the fine-structure-changing collision [i.e,Cs(7P_ 1/2 )+Cs(6S)Cs(7P_ 3/2 )+Cs(6S)]is 3.5×10 -14 cm 2.Populations of the n 2L(nL=7p,6D)states of Cs atoms by photodissociation of Cs_2 molecules through the use of the fixed frequence line 441.6nm of a He-Cd laser radiation are produced.Combining ratios of atomic to molecular fluorescence at the Cs density range between 1 and 9×10 15 cm -3 ,the ratios of collisional excitation transfer rate coefficients and the predissociation rates are obtained.The cross section for the fine-structure-changing collision [i.e,Cs(7P_ 1/2 )+Cs(6S)Cs(7P_ 3/2 )+Cs(6S)]is 3.5×10 -14 cm 2.

Jiguang zazhiJan 1, 20040 citations

\mathrm{Cs}(6p{}^{2}{P}_{3/2})

atoms was measured by scanning the wave number of a probe laser light polarized perpendicular to the field. The population of each sublevel

6p{}^{2}{P}_{{3/2,m}_{j}}

of the dissociated atoms was determined from the line intensities in the

{m}_{j}

-resolved excitation spectrum. The unequal population between the

6p{}^{2}{P}_{3/2,+|{m}_{j}|}

and $6p{}^{2}{P}_{3/2,\ensuremath{-}|{m}_{j}|}$ levels (atomic orientation) was observed and it was enhanced as the magnetic-field strength was increased. The atomic orientation is shown to be induced by the interference between the indirect predissociation, which occurs by a combination of the spin-orbit coupling of the $D{}^{1}{\ensuremath{\Sigma}}_{u}^{+}$ state with the ${(2)}^{3}{\ensuremath{\Pi}}_{0u}$ state and the L-uncoupling and Zeeman interactions between the ${(2)}^{3}{\ensuremath{\Pi}}_{0u}$ and dissociative ${(2)}^{3}{\ensuremath{\Sigma}}_{u}^{+}$ states, and the dissociation following a direct excitation to the ${(2)}^{3}{\ensuremath{\Sigma}}_{u}^{+}$ state, which is allowed by spin-orbit coupling of the ${(2)}^{3}{\ensuremath{\Sigma}}_{u}^{+}$ state with the $B{}^{1}{\ensuremath{\Pi}}_{u}$ state. It is demonstrated that the atomic orientation is produced by the photodissociation in the presence of an external magnetic field even when all degenerated molecular $M=J,\dots{},0,\dots{},\ensuremath{-}J$ sublevels are excited by a light polarized linearly along the field.