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 the Physical Society of Japan

Two-Photon Ionization of Cs2in the Wavelength Range 5300-6200 Å

Hidetoshi Suemitsu, Shinji Imai, Eiji Yoshida, Hiroaki Imanishi, Ichirou Naba

Published Jun 15, 1990• 4 citations
Publisher

Abstract

The relative cross sections of the production of Cs + and Cs 2 + ions through the two-photon ionization of Cs 2 were measured in the 5300-6200 Å wavelength range. A linear polarized dye laser was operated in the CW mode as a light source. The results showed that (1) the cross sections for Cs + ions have a broad peak at around 5570 Å and the threshold at around 6010 Å, and (2) those for Cs 2 + ions have the largest peak at around 5940 Å and many structures in the wavelength range longer than it. Through consideration of the above results, we suggested that Cs + ions are produced not only by two-photon ionization of Cs 2 , but also by a participation of a third photon. The threshold for Cs + ions at around 6010 Å is concerned with the intermediate excited-state Cs 2 (C 1 ∏ u + (ν ′ )), which can be excited from the ground state X 1 Σ g + (ν ′′ =0).

DOI
10.1143/jpsj.59.1981

Related papers

Multiphoton excitation and ionization of atomic cesium with a tunable dye laser

D. Popescu, C. B. Collins, B. W. Johnson +1 more

The two-photon excitation and three-photon ionization of atomic cesium is investigated over the 6550-6950-\AA{} wavelength region with a tunable-dye-laser source having a 0.06-0.08-\AA{} linewidth and a space-charge ionization detector sensitive to a few ions per second. An online data-acquisition computer provides significant signal-to-noise recovery. The resulting dispersion curve for photoionization is interpreted in terms of the two-photon transitions from the ground $6^{2}S_{\frac{1}{2}}$ level to resonant $n^{2}D$ and $n^{2}S$ intermediate states, and represents, to the authors' knowledge, the first such two-photon absorption spectrum of Cs. Transitions from $n=9\mathrm{to}13$ have been recorded for the $6^{2}S_{\frac{1}{2}}\ensuremath{-}n^{2}D_{\frac{5}{2},\frac{3}{2}}$ series and from $n=11\mathrm{to}14$ for the $6^{2}S_{\frac{1}{2}}\ensuremath{-}n^{2}S_{\frac{1}{2}}$ series.

Physical Review A•Mar 1, 1974•70 citations

Multiphoton ionization of Rb2in the wavelength range 620-670 nm

Hidetoshi Suemitsu, H Kitaura, R Yokoyama +2 more

The relative production rates of Rb + and Rb + 2 ions through the multiphoton ionization (MPI) of Rb 2 and the effective order of non-linearity k for these ions were measured in the wavelength range 620-670 nm. The measured results indicated that these ions were produced by two- or three-photon ionization of Rb 2 . The Franck-Condon factors calculated for the transition from the ground state (X 1 Sigma + g ) to the first intermediate state (B 1 Pi u ) were in good agreement with the production rates obtained for Rb + and Rb + 2 ions. From these reasons the authors concluded that in the process of MPI of Rb 2 the transition to the Bu 1 Pi u state plays a crucial role in the production of both ions. The competitive relations between the production processes of Rb + 2 and Rb + ions were derived. In the wavelength range at around 669 nm the ratio of the number of Rb + ions to that of Rb + 2 ions produced through three-photon ionization of Rb 2 was about 4/1.

Journal of Physics B Atomic Molecular and Optical Physics•Nov 14, 1992•4 citations

One- and two-photon production of very highly excited states of caesium

Anthony F. J. van Raan, G. Baum, Wilhelm Raith

Very highly excited p states of Cs with principal quantum numbers 30<or=n<or=85 were produced by one-step photoexcitation with frequency-doubled light from a flash-lamp-pumped dye laser. Field ionization was employed for selective detection. Ionization occurs at field strengths E>or=E min with a sharp threshold. The relation E min (n*) varies as (n*) -4 was verified over a wide range. Two-photon excitation to a very high state via a virtual intermediate state leads to immediate ionization of most of the excited atoms; in this case the ion signal as a function of the light intensity I is not proportional to I k , k>or=2, whereas a direct two-photon transition into the continuum yields proportionality with I 2 .

Journal of Physics B Atomic and Molecular Physics•May 11, 1976•12 citations

Multiphoton Ca2+production occurring before the onset of Ca+saturation: is it a fingerprint of direct double ionization?

Ioannis Liontos, S. Cohen, A. Lyras

Singly and doubly charged Ca ions have been produced by multiphoton excitation of Ca vapour with 5 ns, low intensity (⩽3 × 10 11 W cm −2 ) dye-laser pulses in the 675–685 nm wavelength range, including the four-photon 4s 2 1 S 0 → 4p 2 1 S 0 excitation. The intensity and wavelength dependence of the ion yields was recorded as well as the fluorescence emission from excited states of the Ca ion in an effort to identify the excitation pathways leading to single and double ionization. Unambiguous evidence for the absorption of at least two photons above the first ionization threshold was recorded, in agreement with earlier results for Mg and Sr obtained under similar conditions. However, certain characteristics of the process differ significantly from those of the earlier results, despite the apparent similarity in both the atomic structure and the excitation scheme. The most striking and unexpected finding is that for a certain wavelength, the Ca 2+ yield is observable well before the saturation intensity of Ca + and, moreover, it grows with intensity and saturates in parallel with the Ca + yield. Possible mechanisms behind this outcome are discussed in detail as well as their implications for the multiphoton multiple ionization of complex atoms. Our tentative conclusion is that the occurrence of doubly charged ion production before the singly charged ion saturation should not be considered as 'synonymous' with direct (or non-sequential) multiphoton double ionization.

Journal of Physics B Atomic Molecular and Optical Physics•Apr 13, 2010•8 citations

Two-photon ionization measurements on atomic caesium by means of an argon ion laser

Ernst H.A. Granneman, Marnix J. van der Wiel

Measurements are reported of two-photon ionization probabilities in atomic Cs at the nine wavelengths of the Ar ion laser (5145-4545 AA), the first step of the two-photon process occurring to intermediate levels in the vicinity of the 7 2 P 1/2,3/2 levels. Additional ionization due to molecular Cs was monitored by ion time-of-flight analysis and found to be negligible when choosing proper oven temperatures. An absolute scale for the two-photon rates is provided by normalization on a one-photon UV cross section. Comparison of our data with calculations based on quantum defect Coulomb wavefunctions shows discrepancies of up to four orders of magnitude.

Journal of Physics B Atomic and Molecular Physics•Jul 11, 1975•43 citations

Two-photon ionization of helium for 23S and 21S states

Ravi Sharma, K. C. Mathur

Two-photon ionization of He atom from its excited metastable2^{3}Sand2^{1}Sstates is studied within the framework of the perturbation theory. Cross sections and ratios for circularly and linearly polarized laser light are obtained in the wavelength ranges 3180-3950 Å and 3650-5100 Å for2^{3}Sand2^{1}Sstates, respectively. The effects of the quasi-resonant intermediate states and the states omitted in the truncated summation method are analyzed.

IEEE Journal of Quantum Electronics•Dec 1, 1979•1 citation
The relative cross sections of the production of Cs + and Cs 2 + ions through the two-photon ionization of Cs 2 were measured in the 5300-6200 Å wavelength range. A linear polarized dye laser was operated in the CW mode as a light source. The results showed that (1) the cross sections for Cs + ions have a broad peak at around 5570 Å and the threshold at around 6010 Å, and (2) those for Cs 2 + ions have the largest peak at around 5940 Å and many structures in the wavelength range longer than it. Through consideration of the above results, we suggested that Cs + ions are produced not only by two-photon ionization of Cs 2 , but also by a participation of a third photon. The threshold for Cs + ions at around 6010 Å is concerned with the intermediate excited-state Cs 2 (C 1 ∏ u + (ν ′ )), which can be excited from the ground state X 1 Σ g + (ν ′′ =0).
The two-photon excitation and three-photon ionization of atomic cesium is investigated over the 6550-6950-\AA{} wavelength region with a tunable-dye-laser source having a 0.06-0.08-\AA{} linewidth and a space-charge ionization detector sensitive to a few ions per second. An online data-acquisition computer provides significant signal-to-noise recovery. The resulting dispersion curve for photoionization is interpreted in terms of the two-photon transitions from the ground 62S126^{2}S_{\frac{1}{2}}62S21​​ level to resonant n2Dn^{2}Dn2D and n2Sn^{2}Sn2S intermediate states, and represents, to the authors' knowledge, the first such two-photon absorption spectrum of Cs. Transitions from n=9to13n=9\mathrm{to}13n=9to13 have been recorded for the $6^{2}S_{\frac{1}{2}}\ensuremath{-}n^{2}D_{\frac{5}{2},\frac{3}{2}}$ series and from n=11to14n=11\mathrm{to}14n=11to14 for the $6^{2}S_{\frac{1}{2}}\ensuremath{-}n^{2}S_{\frac{1}{2}}$ series.
The relative production rates of Rb + and Rb + 2 ions through the multiphoton ionization (MPI) of Rb 2 and the effective order of non-linearity k for these ions were measured in the wavelength range 620-670 nm. The measured results indicated that these ions were produced by two- or three-photon ionization of Rb 2 . The Franck-Condon factors calculated for the transition from the ground state (X 1 Sigma + g ) to the first intermediate state (B 1 Pi u ) were in good agreement with the production rates obtained for Rb + and Rb + 2 ions. From these reasons the authors concluded that in the process of MPI of Rb 2 the transition to the Bu 1 Pi u state plays a crucial role in the production of both ions. The competitive relations between the production processes of Rb + 2 and Rb + ions were derived. In the wavelength range at around 669 nm the ratio of the number of Rb + ions to that of Rb + 2 ions produced through three-photon ionization of Rb 2 was about 4/1.
Very highly excited p states of Cs with principal quantum numbers 30<or=n<or=85 were produced by one-step photoexcitation with frequency-doubled light from a flash-lamp-pumped dye laser. Field ionization was employed for selective detection. Ionization occurs at field strengths E>or=E min with a sharp threshold. The relation E min (n*) varies as (n*) -4 was verified over a wide range. Two-photon excitation to a very high state via a virtual intermediate state leads to immediate ionization of most of the excited atoms; in this case the ion signal as a function of the light intensity I is not proportional to I k , k>or=2, whereas a direct two-photon transition into the continuum yields proportionality with I 2 .
Singly and doubly charged Ca ions have been produced by multiphoton excitation of Ca vapour with 5 ns, low intensity (⩽3 × 10 11 W cm −2 ) dye-laser pulses in the 675–685 nm wavelength range, including the four-photon 4s 2 1 S 0 → 4p 2 1 S 0 excitation. The intensity and wavelength dependence of the ion yields was recorded as well as the fluorescence emission from excited states of the Ca ion in an effort to identify the excitation pathways leading to single and double ionization. Unambiguous evidence for the absorption of at least two photons above the first ionization threshold was recorded, in agreement with earlier results for Mg and Sr obtained under similar conditions. However, certain characteristics of the process differ significantly from those of the earlier results, despite the apparent similarity in both the atomic structure and the excitation scheme. The most striking and unexpected finding is that for a certain wavelength, the Ca 2+ yield is observable well before the saturation intensity of Ca + and, moreover, it grows with intensity and saturates in parallel with the Ca + yield. Possible mechanisms behind this outcome are discussed in detail as well as their implications for the multiphoton multiple ionization of complex atoms. Our tentative conclusion is that the occurrence of doubly charged ion production before the singly charged ion saturation should not be considered as 'synonymous' with direct (or non-sequential) multiphoton double ionization.
Measurements are reported of two-photon ionization probabilities in atomic Cs at the nine wavelengths of the Ar ion laser (5145-4545 AA), the first step of the two-photon process occurring to intermediate levels in the vicinity of the 7 2 P 1/2,3/2 levels. Additional ionization due to molecular Cs was monitored by ion time-of-flight analysis and found to be negligible when choosing proper oven temperatures. An absolute scale for the two-photon rates is provided by normalization on a one-photon UV cross section. Comparison of our data with calculations based on quantum defect Coulomb wavefunctions shows discrepancies of up to four orders of magnitude.