Journal of Physics B Atomic and Molecular Physics

Measured lifetimes in zinc I and zinc II using the electron-photon delayed-coincidence technique

David A. Shaw, GEORGE C. KING, A Adams

Published Jan 28, 1978• 12 citations

Abstract

The electron-photon delayed-coincidence technique has been used to measure the lifetimes of excited states in neutral and singly ionised natural zinc. These states, with their lifetimes, are Zn I: 5 1 S (41.1+or-0.4) ns, 4 1 D (21.1+or-0.4) ns, 6 1 S (103+or-3) ns, 5 1 D (89+or-4) ns; Zn II: 4p 2 P (3.2+or-0.2) ns.

DOI: 10.1088/0022-3700/11/2/009

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Journal of Physics B Atomic and Molecular Physics

Measured lifetimes in zinc I and zinc II using the electron-photon delayed-coincidence technique

David A. Shaw, GEORGE C. KING, A Adams

Published Jan 28, 1978• 12 citations

Publisher

Abstract

DOI: 10.1088/0022-3700/11/2/009

Related papers

Measured lifetimes in cadmium using the electron-phonon delayed coincidence technique

D Cvejanović, A Adams, GEORGE C. KING

Journal of Physics B Atomic and Molecular PhysicsJul 11, 19765 citations

Coincidence measurements of electron impact excitation of the 41P1state of Zn

Mariusz Piwiński, Łukasz Kłosowski, D. Dziczek +1 more

Journal of Physics Conference SeriesNov 5, 20120 citations

Determination of the lifetime of the 4p 1 P 0 state of calcium by electron photon coincidence

M.A.K. Elfayoumi

The electron-photon delayed coincidence technique has been used to measure precisely the lifetime for the 4p 1 P 0 state in calcium. The lifetime of this state was obtained by measuring the time correlation spectrum between the inelastically scattered electrons and the corresponding de-excitation photons. By using the least-squares fitting program to fit Gale's equation to the data points, a value of (4.15±0.17) ns was obtained. The result was compared to some of the earlier experimental measurements.The electron-photon delayed coincidence technique has been used to measure precisely the lifetime for the 4p 1 P 0 state in calcium. The lifetime of this state was obtained by measuring the time correlation spectrum between the inelastically scattered electrons and the corresponding de-excitation photons. By using the least-squares fitting program to fit Gale's equation to the data points, a value of (4.15±0.17) ns was obtained. The result was compared to some of the earlier experimental measurements.

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Measured Lifetime of the ( 3p54s ) P13 State of Argon

John L. Morack, Clifford E. Fairchild

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Paul E. Jessop, F. M. Pipkin

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{4\mathrm{p}}^{2}

{\mathrm{P}}_{3\mathrm{/}2}^{\mathrm{o}}

state of Ca II, the

{6\mathrm{p}}^{2}

{\mathrm{P}}_{3\mathrm{/}2}^{\mathrm{o}}

state of Ba II, and the

{4\mathrm{p}}^{2}

{\mathrm{P}}_{3\mathrm{/}2}^{\mathrm{o}}

state of Al III. These measurements are in good agreement with earlier work.

A direct measurement of the natural lifetime for the (

3{p}^{5}4s

)

^{3}P_{1}

state of argon has been made using a modified delayed-coincidence method. Argon atoms are repetitively excited by pulses of electrons. For each pulse, the decaying light signal is sampled for a time $\ensuremath{\Delta}t$ at some delay time

{t}_{1}

after the excitation is terminated. The exponential decay is then reconstructed as the delay time is changed. Collision effects are not important in the pressure region (5.0\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}6}$-2.0\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ Torr) of the experiment and the effects due to cascading are eliminated by keeping the energy of the bombarding electrons low enough so that excitation of the

3{p}^{5}4p

levels is negligible. The measured lifetime is dependent upon the argon pressure, and this effect is attributed to resonance trapping; a value of 21\ifmmode\pm\else\textpm\fi{}2 nsec is obtained for the natural lifetime by using the existing theories of resonance trapping to extrapolate the data to zero pressure.

A delayed-coincidence technique has been used to measure the lifetime of the

5d6p^{1}F_{3}

state of atomic barium. An intermediate,

6s5d^{1}D_{2}

metastable state of barium atoms in an atomic beam was populated by electron bombardment, and a pulsed cw laser was employed to excite atoms from the metastable state to the

5d6p^{1}F_{3}

state. A time-to-amplitude convertor was used to measure the time distribution of the fluorescent light. The value obtained for the lifetime was (44.5\ifmmode\pm\else\textpm\fi{}1.8) nsec.