G Jonsson

Natural Radiative Lifetimes and Stark-Shift Parameters in the 4p2 Configuration in Ca I

The radiative lifetimes in the doubly excited 4p2 configuration in Ca were determined using the delayed coincidence technique. The measured states were populated either with two-step laser excitation from the 4s2 1S0 ground state or with single-step excitation starting from a metastable state. The metastable states were populated by collisions in a discharge. The following lifetime values were obtained: τ(4p2 1D2) = 16.3(20) ns, τ(4p2 1S0) = 14.4(7) ns and τ(4p2 3P0,1,2) = 6.9(4) ns. Stark shift parameters in the same configuration were measured using an atomic beam passing between electric field plates. The following results were obtained: α0(4p2 1S0) = -32.2(16) MHz (cm/kV)2, α0(4p2 1D2) = 1.8(2) MHz (cm/kV)2 and α2(4p2 1D2) = 1.15(10) MHz (cm/kV)2. Additional measurements yielded τ(4s5f1F3) = 60(3) ns, τ(4s4d3D1,2,3) = 13.0(5) ns and α0 (4s6s 1S0) = 6.98(35) MHz (cm/kV)2.

Natural radiative lifetimes in the2S1/2 and2D5/2,3/2 sequences of aluminum

Natural radiative lifetimes have been measured for the 3s2ns2S1/2 (n≦10) and 3s2nd2D5/2,3/2 (n≦11) sequences of aluminum using pulsed laser excitation of an atomic beam. The investigated states were populated from the ground configuration using UV pulses of wavelength down to 210 nm produced by a Nd: YAG- or an excimer-pumped dye-laser system. TheS-state lifetimes increase regularily with increasing principal quantum number but this is not the case for theD sequence.

Hyperfine structure and isotope shift of highly excited barium-I states

High-resolution laser-spectroscopy measurements of hyperfine structure and isotope shifts were performed for the 6snd1D2 sequence of Ba-I in the regionn=12–24. Stepwise laser excitations of a collimated atomic beam were used. A strong influence on the hyperfine structure is observed at the perturbation atn=14, caused by interaction with the 5d7d configuration. Whereas the isotope shift for the even isotopes stays essentially constant with increasingn, the odd isotopes exhibit a strong change, indicating hyperfine-induced shifts.

Experimental and Theoretical-studies of the 4s2 N P 2p Sequence In Neutral Gallium

Using timeresolved laser spectroscopy lifetime values as well as hyperfine coupling constants have been determined for the 4s2np2P3/2 (n=7–11) states in69Ga and71Ga. Theoretical calculations of hyperfine structures based on manybody perturbation theory have been performed in the same sequence (n = 4–8) for both finestructure components. The theoretical values are compared with existing experimental data.

Natural Radiative Lifetimes and Hyperfine-structure of the 4s^(2)6p^(2p)_(3/2,1/2) Levels of Gallium

Natural radiative lifetimes and the signs of previously determined hyperfine coupling constants were determined for the 4s26p2P32,12 levels of gallium. The lifetimes were found to be 167(4) and 172(9) ns, respectively. In addition, the quadrupole moments of 69Ga [0.17(3) b] and 71Ga [0.10(2) b] were deduced, and the isotope shifts in the 639.7 and 641.3 nm Ga lines were determined.

Natural Radiative Lifetimes In the 1p1 and 1f3 Sequences of Sr I

We have measured radiative lifetimes in the 5s n p1P1 (n=5–29) and 5s n f1F3 (n=4–11) Rydberg series in neutral strontium. The measurements were performed with single-step laser excitation starting from the ground state or from a metastable state populated by collisions. The decay photons were detected using delayed coincidence technique or a transient recorder. The presence of configuration interaction in the 5s n p1P1 series can be observed aroundn=8. The perturbation in the 5s n f1F3 series is not reflected in the behaviour of the lifetime values.

Hyperfine structure and radiative lifetimes in the 3s2n p2P3/2 sequence of Al-27 using time resolved laser spectroscopy

Using time-resolved laser spectroscopy we have determined the hyperfine structure in the 3s2n p2P3/2 sequence of27Al (I=5/2). The magnetic-dipole interaction constants were found to scale withn*−2.85 (n* is the effective principal quantum number) in the investigated regionn=6–12. Significant quadrupole interaction constants were obtained forn=6–9. The measured radiative lifetimes forn=6–12 scale withn*2.

Hyperfine-structure Study of the 72p3/2,82p3/2 and 92p3/2 States In Na-23 Using Quantum-beat Spectroscopy

We have performed hyperfine-structure measurements on the 7, 8 and 9 2P3/2 states in 23Na using quantum-beat spectroscopy. The light from a pulsed dye laser, pumped by an excimer laser, was frequency-doubled and used to excite sodium atoms in an atomic beam. The fluorescence light was recorded by a transient digitizer and the transients were added in a digital memory and transferred to a mini-computer for calculations. For the magnetic-dipole and electric-quadrupole constants, a and b, we have obtained the following values: 7 2P3/2; a = 0.82(1) MHz, b = 0.13(3)MHz 8 2P3/2; a = 0.535(15) MHz, b = 0.070(25)MHz 9 2P3/2; a = 0.36(1) MHz, b = 0.045(15)MHz