Accurate lifetime measurements of the lowest<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>P</mml:mi></mml:mrow><mml:mrow><mml:mfrac><mml:mrow><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:mfrac></mml:mrow><mml:mrow /><mml:mrow /><mml:mrow /><mml:mprescripts /><mml:mrow /><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:mrow /><mml:mrow /></mml:mmultiscripts></mml:mrow></mml:math>states in neutral lithium and s

Gaupp, A.; Kuske, P.; Andrä, H. J.

doi:10.1103/physreva.26.3351

Cited by 178 publications

(67 citation statements)

References 62 publications

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“…Fits to decays where these parameters were variables reproduced the decay curves more closely and yielded the individual run values tabulated in Tables 2 and 3. A study state analysis for Na( 2 P) from reaction 2′ and 3 yields which can be rearranged to where k 3 is the inverse of the [Na( 2 P)] radiative lifetime, (16.40 ( 0.03) × 10 -9 s. 31 In principle, we can determine [Na( 2 P)] from its observed chemiluminescent signal (CL) in the reaction region in front of the Na PMT:…”

Section: Resultsmentioning

confidence: 99%

“…Since the Na PMT optics were arranged so that the resonance lamp output fills the Na PMT field of view, with the lamp on the Na PMT records a signal which is the sum of CL plus a fluorescence signal equal to where k hν ) σF/(1 + R 2 ) 1/2 , σ is the Na( 2 Sf 2 P) absorption crosssection of 1.85 × 10 -11 cm 2 derived from the excited-state radiative lifetime, 31 F is the measured resonance lamp photon flux though the PMT observation volume, and R is the overlap integral between the room temperature ground-state Na absorption line and the lamp output spectra. 2 The value of R can be obtained from the ratio of the Doppler broadened half-width of the lamp Na emission line and the room temperature Doppler broadened absorption width of the Na in the low-pressure flow reactor, which can be approximated by the square root of the ratio of the lamp operating temperature (600 K) divided by the flow tube gas temperature (290 K), to give R ) 1.44.…”

Section: Resultsmentioning

confidence: 99%

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Chemical Kinetics of the NaO (A ²Σ⁺) + O(³P) Reaction

et al. 2000

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Recent evidence has shown that the mesospheric sodium nightglow, a chemiluminescent process which produces atomic sodium D-line radiation in the Earth's upper atmosphere, proceeds through the first excited (A 2 Σ + ) electronic state of NaO. The rate of D-line radiation production is proportional to the rate constant for the reaction of NaO(A 2 Σ + ) + O( 3 P) and its branching ratio to produce excited Na( 2 P) rather than ground-state Na( 2 S). The only previously published measurement of the NaO + O( 3 P) reaction rate and branching ratio was performed under slow flow conditions and almost certainly primarily represents the reaction of groundstate NaO (X 2 Π). We present low-pressure measurements of the NaO + O reaction kinetics using an NaO source reaction known to produce NaO in the (A 2 Σ + ) state and determine the 290 K reaction rate constant to be (5.1 ( 1.8) × 10 -10 cm 3 s -1 and the branching ratio to produce Na( 2 P) to be 0.14 ( 0.04. New data on the termolecular rate coefficient for the reaction Na + O 2 + He f NaO 2 + He at 290 K are also presented.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Chemical Kinetics of the NaO (A ²Σ⁺) + O(³P) Reaction

et al. 2000

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“…The Einstein B coefficient, giving the absorption probability per unit time of a photon of multipolarity (Jλ) leading from a state I with angular momentum J I , to a state F with angular momentum J F , is B (λ) (42) where we use the notation [J] = 2J + 1. The corresponding Einstein A coefficient, giving the spontaneous emission probability for transitions from state I to state F with E I − E F =hω is, of course, given by…”

Section: Multipole Potentials and Transition Amplitudesmentioning

confidence: 99%

“…Equations (42)(43)(44) are used in the following sections to evaluate multipole-transition amplitudes and rates.…”

Section: Multipole Potentials and Transition Amplitudesmentioning

confidence: 99%

Relativistic Calculations of Transition Amplitudes in the Helium Isoelectronic Sequence

Johnson

Plante

Sapirstein

1995

Advances in Atomic, Molecular, and Optical Physics

201

171

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Exact relativistic wave functions for n=1 and n=2 states of heliumlike ions are used to calculate single-photon transition amplitudes for 2 S0.Particular attention is given to the role of negative-energy states in bringing length and velocity forms into agreement, and related quantum electrodynamics issues. This is a reprinted version of an article with the same title published in Advances in Atomic, Molecular and Optical Physics 35, 225-329 (1995). Figures included in the original article are omitted here.

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“…Because of this, new and more accurate ways of measuring excited state lifetimes are constantly being investigated. Previous methods include time-correlated single photon techniques [4,5,6,7,8,9], beam-foil experiments [5], fast beam measurements [10,11], electron-photon delayed coincidence techniques [12,13], luminescent decay [14,15], linewidth measurements [16], photoassociative spectroscopy [17], and quantum jump methods [18].…”

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confidence: 99%

Precision lifetime measurements of a single trapped ion with ultrafast laser pulses

et al. 2006

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We report precision measurements of the excited state lifetime of the 5p 2 P 1/2 and 5p 2 P 3/2 levels of a single trapped Cd + ion. The ion is excited with picosecond laser pulses from a mode-locked laser and the distribution of arrival times of spontaneously emitted photons is recorded. The resulting lifetimes are 3.148 ± 0.011 ns and 2.647 ± 0.010 ns for 2 P 1/2 and 2 P 3/2 respectively. With a total uncertainty of under 0.4%, these are among the most precise measurements of any atomic state lifetimes to date. Here we report excited state lifetime measurements using a time-correlated single photon counting technique on a single atom. This method, designed especially to eliminate common systematic errors, involves selective excitation of a single trapped ion to a particular excited state (lifetime of order nanoseconds) by an ultrafast laser pulse (duration of order picoseconds). Arrival of the spontaneously-emitted photon from the ion is correlated in time with the excitation pulse, and the excited state lifetime is extracted from the distribution of time delays from many such events.By performing the experiment on a single trapped ion, we are able to eliminate prevalent systematic errors, such as: pulse pileup that causes multiple photons to be collected within the time resolution of the detector, radiation trapping or the absorption and re-emission of radiation by neighboring atoms, atoms disappearing from view before decaying, and subradiance or superradiance arising from coherent interactions with nearby atoms. By using ultrafast laser pulses, we eliminate potential effects from applied light during the measurement interval.With this setup, at most one photon can be emitted following an excitation pulse. While this feature is instrumental in eliminating the above systematic errors, it would appear that this signal would require large integration times for reasonable statistical uncertainties. However, with a lifetime of only a few nanoseconds, millions FIG. 1: The experimental apparatus. (a) A picosecond mode locked Ti:Saph laser is tuned to four times the resonant wavelength for either the 5p 2 P 1/2 or the 5p 2 P 3/2 level of Cd + . Each pulse is then frequency-quadrupled through non-linear crystals, filtered from the fundamental and second harmonic, and directed to the ion. An amplified cw diode laser is also frequency quadrupled and tuned just red of the 2 P 3/2 transition for Doppler cooling of the ion within the trap. Acoustooptic modulators (AOM) are used to switch on and off the lasers as described in the text. Photons emitted from the ion are collected by an f /2.1 imaging lens and directed toward a photon-counting photo multiplier tube (PMT). The output of the PMT provides the start pulse for the time to digital converter (TDC), whereas the stop pulse is provided by the reference clock of the mode-locked laser. of such excitations can be performed each second, thus potentially allowing sufficient data for a statistical error of under 0.1% to be collected in a matter of minutes [6].A diagram of th...

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Accurate lifetime measurements of the lowestP122states in neutral lithium and s

Cited by 178 publications

References 62 publications

Chemical Kinetics of the NaO (A ²Σ⁺) + O(³P) Reaction

Chemical Kinetics of the NaO (A ²Σ⁺) + O(³P) Reaction

Relativistic Calculations of Transition Amplitudes in the Helium Isoelectronic Sequence

Precision lifetime measurements of a single trapped ion with ultrafast laser pulses

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Accurate lifetime measurements of the lowestP122states in neutral lithium and s

Cited by 178 publications

References 62 publications

Chemical Kinetics of the NaO (A 2Σ+) + O(3P) Reaction

Chemical Kinetics of the NaO (A 2Σ+) + O(3P) Reaction

Relativistic Calculations of Transition Amplitudes in the Helium Isoelectronic Sequence

Precision lifetime measurements of a single trapped ion with ultrafast laser pulses

Contact Info

Product

Resources

About

Chemical Kinetics of the NaO (A ²Σ⁺) + O(³P) Reaction

Chemical Kinetics of the NaO (A ²Σ⁺) + O(³P) Reaction