Power broadening of the Na-D lines in a flame—I. Time-dependent spectral and spatial properties of a flashlamp pumped dye laser

Prior to power broadening experiments on the Na-D lines in a flame (described in Part II), we investigated the time-dependent spectral and spatial properties of a flashlamp-pumped pulsed dye laser (pulse duration about 800 ns, FWHM), with Rhodamine-6G in methanol as dye liquid and an interference filter combined with a Fabry-Pérot etalon as bandwidth-restricting elements in the cavity. An experimental set-up is described that permits measurements of time-dependent spectra with a time-resolution of 10 ns and a spectral resolution of 2.5 × 10⁵. Results are given for different concentrations of the dye solution and for two different bandwidth settings of the laser. In general the spectral profiles at different moments during the pulse are well described by Gaussian curves. The spatial profiles at different moments during the pulse are best fitted by Lorentzian curves. At small concentrations of the dye solution, the time behaviour of the shift and the bandwidth are in (qualitative) agreement with theoretical predictions, i.e. a narrowing of the bandwidth and a shift to longer wavelengths of the line centre.     

Influence of the chain length of long molecules on the equation of state in binary gas-liquid mixtures

The simple Flory-Huggins model can be combined with the lattice gas as was done by Tompa and others. Here the same method is used to obtain the van der Waals equation of state for a binary gas-liquid system containing a solute consisting of segmented molecules. The simplified equation of state developed here is useful for the study of the critical properties of such systems, in particular, the dependence of the various parameters on the chain length of the molecules.     

Levels in179W studied in the181Ta(p, 3n) reaction by on-line electron and gamma ray spectroscopy

Levels in¹⁷⁹W have been deduced from in-beam gamma and conversion electron studies of the¹⁸¹Ta(p, 3n)¹⁷⁹W reaction. The gamma-ray spectrum was studied with Ge(Li) detectors and a crystal diffraction spectrometer; the conversion electrons were measured with a broad range transport solenoid Si(Li) spectrometer. The multipolarities of some 50 transitions could be determined. Coriolis mixing of the Nilsson orbits withN=6 was calculated.     

Fragmentation of gold projectiles: From evaporation to total disassembly

We have studied the fragmentation of Au projectiles interacting with targets of C, Al and Cu at an incident energy ofE/A=600 MeV. The employed inverse kinematics allowed a nearly complete detection of projectile fragments with chargeZ≧2. The recorded fragmentation events were sorted according to three observables, the multiplicityM _lp of light charged particles, the largest atomic numberZ _max within an event, and a new observable,Z _bound, representing the sum of the atomic numbersZ of all fragments withZ≧2. Using these observables, the impact parameter dependence of the fragmentation process was investigated. For all three targets, a maximum mean multiplicity of 3 to 4 intermediate mass fragments (IMFs) is observed. The corresponding impact parameters range from central collisions for theC target to increasingly peripheral collisions for the heavier targets. It is found that the correlation between the IMF multiplicity andZ _bound, extending from evaporation type processes (largeZ _bound) to the total disassembly of the projectile (smallZ _bound), is independent of the target nucleus. This universal behaviour may suggest an — at least partial — equilibration of the projectile fragment prior to its decay.     

Evidence for dipole-quadrupole-octupole mixing in the 902 keV 2 → 2 transition in W

From known conversion coefficients and angular correlations combined with the γ-ray decay deduced from the ¹⁸¹Ta(p, 2n¹⁸⁰W reaction it is found that the 1007 → 104 keV (2⁻ → 2⁺) transition in ¹⁸⁰W has mixing parameters δ₁ = −0.16 ± 0.07 and δ₂ = −0.64 ± 0.17 for M2/E1 and E3/E1, respectively     

Reactions of 14N and 16O ions with light nuclei at Elab = 16–58 MeV

Yield curves for formation of ⁷Be and other radio-nuclides from bombardment of C, Al and Si targets with 16–58 MeV ¹⁴N and ¹⁶O ions were measured. The ⁷Be yields disagree by several orders of magnitude with Hauser-Feshbach and transition-state predictions. The other yields are in order-of-magnitude agreement with nucleon and/or α-particle evapolation calculations.