Determination of Radiative Lifetimes In the 3d(10)np(2)p Sequence of Neutral Copper By Time-resolved Vuv Laser-spectroscopy

Lifetimes in the 3d(10)np(2)P sequence in neutral copper were measured by time-resolved laser spectroscopy. Excitation from the ground state was performed with pulsed laser radiation in the; vuv spectral region, generated by resonant sum-difference four-wave mixing in krypton gas. The lifetimes were evaluated from recorded optical transients. For the np(2)P(J) states we find the following: tau(n = 6, 5 = 3/2) = 5.2(8) ns, tau(6, 1/2) = 25.1(10) ns, tau(7; 3/2) = 15.0(12) ns, tau(7, 1/2) = 4.0(8) ns, tau(8,3/2) = 31(2) ns, tau(8, 1/2) = 15.8(12) us, tau(9, 3/2) = 123(6) ns, and tau(9, 1/2) = 51(6) ns. The data are compared with a recent multiconfiguration Hartree-Fock calculation

Measurements of excited state lifetimes and oscillator strengths in Pt II

We report on radiative lifetime measurements of short-lived states in singly ionized platinum by excitation with pico-second laser pulses and subsequent time-resolved detection. The upper levels were populated from metastable ion levels in a laser-generated plasma using radiation in the UV/VUV spectral range. The following lifetimes were obtained: tau(5d(8)(F-3(4))6p(1/2), J = 7/2) = 3.9(3) ns, tau(5d(8)(F-3(4))6p(3/2), J = 9/2) = 3.5(3) ns and tau(5d(8)(F-3(3))6p(1/2), J = 5/2) = 2.6(3) ns. By using relative intensities of the lines found in the literature, oscillator strengths were determined

Two-color Time-resolved Spectroscopy of Helium Using High-order Harmonics

The radiative lifetime of the 1s2p(1)P state of helium is measured in a two-colour ionization experiment with a 5% accuracy. The state is excited by the 13th harmonic of a tunable 80 ps laser and ionized by a synchronous ultraviolet laser, with a variable time delay. This experiment demonstrates that the high harmonics generated in a jet of rare gas exposed to an intense laser field provide a tunable short-pulse xuv source ideally suited for pump/probe type of studies and, in particular, short lifetime measurements

Experimental Pd II oscillator strengths and the palladium abundance in the HgMn-type star chi Lupi

Experimental oscillator strengths for 19 ultraviolet lines of Pd II have been derived from measurements of line intensities in calibrated Fourier transform spectra, combined with picosecond-pulse laser measurements of radiative lifetimes. Five of these 19 lines, in addition to other Pd nr lines, are present in Hubble Space Telescope/Goddard High-Resolution Spectrograph echelle spectra of the chemically peculiar HgMn star chi Lupi, yielding a palladium abundance of log (N-Pd) = +5.0, which is 3.3 dex above the solar abundance. Theoretical oscillator strengths have been calculated for all strong ultraviolet transitions associated with the lowest odd-parity configuration of Pd II

Interference effects in two-photon ATI by multiple orders high harmonics with random or locked phases

We numerically study 2-photon processes using a set of harmonics from a Ti:Sapphire laser and in particular interference effects in the Above Threshold Ionization spectra. We compare the situation where the harmonic phases are assumed locked to the case where they have a random distribution. Suggestions for possible experiments, using realistic parameters are discussed.Comment: 11 pages, 13 figures, LaTe

Determination of radiative lifetimes of excited states in neutral gold using time-resolved vacuum-ultraviolet laser spectroscopy

Natural radiative lifetimes of the states in the highly perturbed 5d10np 2P sequence in neutral gold, Au i, for n=69, as well as of four of the perturbing 5d96s6p 2P states, have been measured. This was done by direct excitation from the ground state with short-pulse vacuum-ultraviolet laser light and time-resolved detection of the laser-induced fluorescence. We found the lifetimes to be (6p 2P1/2)=6.2(2) ns, (6p 2P3/2)=4.7(2) ns, (7p 2P1/2)=6.4(7) ns, (7p 2P3/2)=5.3(7) ns, (8p 2P1/2)=63(3) ns, (8p 2P3/2)=24(2) ns, (9p 2P1/2)=28(2) ns, and (9p 2P3/2)=75(4) ns. For the perturbing states (two states of each term have been observed) we found (2P1/2, 60 983.05 cm-1)=17.5(10) ns, (2P1/2, 62 540.65 cm-1)=6.7(7) ns, (2P3/2, 58 826.30 cm-1)=2.1(15) ns, and (2P3/2, 63 005.62 cm-1)=2.7(15) ns. Furthermore, we have investigated the hyperfine structure of the 6p 2P3/2 state. © 1994 The American Physical Society