Optical polarization of neutron-rich sodium isotopes and β\beta-NMR measurements of quadrupole moments

The nuclear quadrupole moments of neutron-rich sodium isotopes are being investigated with the help of in-beam polarization by optical pumping in combination with $\beta$-NMR techniques. First measurements have yielded the quadrupole splittings of NMR signals in the lattice of LiNbO$_{3}$ for the isotopes $^{26}$Na, $^{27}$Na and $^{28}$Na. Interaction constants and ratios of the electric quadrupole moments are derived. In view of future experiments, $\beta$-decay asymmetries for the sequence of isotopes up to the $N$=20 neutron shell closure, $^{26-31}$Na, have been measured

Laser spectroscopy investigation of the nuclear moments and radii of lutetium isotopes

Collinear laser spectroscopy experiments in the LuI transition $5d6s\!^{2} \; ^{2}\!D_{3/2} \rightarrow 5d6s6p \; ^{2}\!D_{3/2}$ were performed on all lutetium isotopes in the range of $^{161-179}$Lu. The nuclear spins, magnetic moments and quadrupole moments were determined from the hyperfine structures observed for 19 ground states and 11 isomers. Variations in the mean square charge radii as a function of neutron number were obtained from the isotope shifts. These data considerably extend the systematics of the properties of nuclei in the upper rare-earth region. A particular feature is the appearance of high-spin and low-spin ground states and isomeric states in the vicinity of the stable $^{175}$Lu, partly arising from aligned neutron pairs. The present results clearly show that the deformation properties are nearly independent of the occupancy and the coupling of single-particle states. Theoretical predictions of deformation are confirmed in a consistent description of the measured radii and quadrupole moments. For all observed states, the spins and magnetic moments allow the assignment of rather pure Nilsson configurations

Quadrupole moments and mean-square charge radii in the bismuth isotope chain

Isotope shifts and hyperfine structures of the $^{205, 206, 208, 210, 210m, 212, 213}$Bi isotopes have been studied on the 306.7nm line using gas cell laser spectroscopy. The neutron-rich isotopes are the first isotones of Pb to be measured immediately above the N=126 shell closure. The ground state quadrupole moments of the even--N isotopes increase as neutrons are added or removed from the N=126 shell, but no corresponding increase is observed in the charge radii

Moments and mean square charge radii of short-lived argon isotopes

We report on the measurement of optical isotope shifts for $^{32-40}$Ar and for $^{46}$Ar from which the changes in mean square nuclear charge radii across the N = 20 neutron shell closure are deducted. The investigations were carried out by collinear laser spectroscopy in fast beams of neutral argon atoms. The ultra-sensitive detection combines optical pumping, state-selective collisional ionization and counting of $\beta$-radioactivity. By reaching far into the sd-shell, the results add new information to the systematics of radii in the calcium region (Z $\approx$ 20). Contrary to all major neutron shell closures with N $\geq$ 28, the N = 20 shell closure causes no significant slope change in the development of the radii. Information from the hyperfine structure of the odd-A isotopes includes includes the magnetic moments of $^{33}$Ar (I=1/2) and $^{39}$Ar (I=7/2), and the quadrupole moments of $^{35}$Ar, $^{37}$Ar (I=3/2) and $^{39}$Ar. The electromagnetic moments are compared to shell-model predictions for the sd- and fp-shell. Even far from stability a very good agreement between experiment and theory is found for these quantities. The mean square charge radii are discussed in the framework of spherical SGII Skyrme-type Hartree-Fock calculations

In-situ Measurements of Tropospheric Hydroxyl Radicals by Folded Long-Path Laser Absorption During the Field Campaign POPCORN

Absolutely calibrated in-situ measurements of tropospheric hydroxyl radicals, formaldehyde, sulfur dioxide, and naphthalene (C10H8) were performed by long-path laser absorption spectroscopy during the field campaign POPCORN. The absorption light path was folded into an open optical multiple reflection cell with a mirror separation of 38.5 m. Using a light path length of 1848 m and an integration time of 200 s, the average 1 sigma-detection limits of OH, HCHO, SO2 and C10H8 during POPCORN were 8.710(5) cm(-3): 8.3.10(9) cm(-3), 2.4.10(9) cm(-3), 1.5.10(8) cm(-3), respectively. In total, 392 identifications of OH in air spectra were made in a rural environment between August 5 and August 23, 1994. We present and discuss OH absorption spectra and diurnal OH concentration profiles of three days which are representative for measurements under different pollution conditions during POPCORN. The observed maximum and median OH radical concentrations are 1.3.10(7) OH/cm(3) and 4.0.10(6) OH/cm(3), respectively. The measured diurnal variation of the OH concentration shows a good correlation with the primary formation reaction of OH radicals which is the photolysis of ambient ozone. Deviations from this correlation in the morning and evening hours, when the OH concentration is higher than expected from the ozone photolysis, demonstrate the importance of other photochemical HOx production pathways during POPCORN

Ion beam milling of silica for IR transmission

Ion beam etching is applied to produce specimens less than 1 mu m thick with a free aperture of 4 mm in diameter. Plane specimens which have the same chemical composition and structure as the bulk material can be obtained. Infrared transmission spectra were obtained from fused silica samples Herasil and Suprasil W. The shapes of these transmission spectra are discussed. The absorption bands in the region 5-7 mu m have the same intensity for both glasses independent of the OH content of the silica. They are supposed to be overtones of the basic Si-O vibrations at 9.4 mu m and 12.4 mu m. </jats:p