5s-5p Transitions Research Articles

New spectroscopic data for atomic tungsten XIV

The thirteen times ionized tungsten is isoelectronic with PmI. Wavelengths and transition probabilities for the 5s-5p and 5p-5d transitions of WXIV, identifying the ground state as 4f13 5s2 2F7/2 were calculated. Both, a relativistic Hartree Fock approach, including core-polarization effects, and a purely relativistic multiconfiguration Dirac-Fock method were used for the calculations. Particularly, 5s-5p transitions were compared with experimental results obtained with VUV electron beam ion trap (EBIT) spectroscopy.

Measurement of Population Inversion for FUV Transitions in Kr-like Y IV in a High-Current Reflex Discharge

Kr-like ions are good candidates for FUV lasing since they can be produced in plasmas quite easily. We present results from a spectroscopic investigation of Y IV emission from a high current density, cold cathode reflex discharge. The Y II to Y V emission is recorded in the 200–3000 Å range using photometrically calibrated spectrometers, while the emission of trace aluminum ions serves for plasma diagnostics. The intensities of the Y IV 4d–5p and 5s7–5p transitions strongly increase relative to lines from Y II and Y III with increasing plasma current. The spectra studied here are obtained at a current density of 1.75 A/cm2. Experimental Y IV intensity ratios spanning several excited configurations are compared with collisional radiative predictions of the HULLAC atomic physics package. Good agreement is found for the measured and predicted ratios of 4p55p to 4p55s level populations per statistical weight. Finally, the response of the Kr-like system to a fast, transient excitation pulse is examined using the RADEX code. Large transient gains are predicted for several 5s–5p transitions in Kr-like Y IV.

Tentative identification of the 5s-5p transitions in Pm I-like Au XIX

The EUV spectrum of foil-excited Au ions has been studied in the wavelength range 12–36 nm. The inherent time-resolution of the fast-beam light source has been used to discriminate against a multitude of very short-lived decays of core-excited ions. Two lines have been found which may be identified with the 5s-5p 1/2,3/2 transitions in Pm I-like Au18+. Their wavelengths of (20.58±0.03) nm and (31.37±0.03) nm are close to values predicted by Ellis and Curtis.

Absolute transition probabilities of 5s-5p transitions of Kr I from interferometric measurements in LTE-plasmas

Absolute transition probabilities of nine 5s-5p transitions of Kr I have been evaluated by using the hook method. The plasma was produced in a shock tube. The population density of the 5s-levels was calculated, under the assumption of LTE, from the electron density and the ground state number density measured by means of a dual wavelength interferometer. An evaluation is given which proves the validity of the LTE assumption.

Experimental transition probabilities of 5s-np (n=5,6) transitions of Kr I

The lifetimes of the 5p(5/2)2, 6p(5/2)3 and 6p'(1/2)1 levels of Kr I have been measured by the delayed coincidence method. Relative transition probabilities for eight 5s-5p lines and for twenty-seven 5s-6p lines have been found and for six 5s-5p transitions, absolute values are given. Comparison is made with experimental and theoretical values.

Isotope shift in molybdenum

The isotope shift in molybdenum has been studied in 16 lines of the arc and 6 lines of the spark spectrum for all stable isotopes by means of a photoelectric recording Fabry-Perot spectrometer with digital data processing. Mass shift and field shift were separated by two independent methods and were compared with the results of Hartree-Fock calculations. In the field shift large crossed-second-order effects ind5s7S and5S were observed, which could be explained quantitatively by theory. The changes in mean square nuclear charge radii were evaluated from three 5s-5p transitions between different multiplets. The relativeδ〈r2〉 values are: [92, 94] 1; [94, 96] 0.854(3); [96, 98] 0.665(4); [98, 100] 1.003(5); [95, 97] 0.703(5);. [94, 95] 0.270(4); [96, 97] 0.119(5). The absolute values can be obtained withδ〈r2〉92, 94=0.226(19)fm2.