The absorption spectrum of thin films of CfCIs was measured at 298, 77, and 4°K in the range 6000-46000 em-I. Interpretation of the results was based on systematic variation of energy level parameters over the actinide series. Electrostatic, spin-orbit, and configuration interaction terms were calculated by diagonalization of the complete interaction matrices and a least squares fitting process involving 27-level assignments. Compared to the energies of the firstf-+d transitions observed in lighter actinide trichlorides, the corresponding band in CfCIs appears to occur at an anomalously low energy.

Low temperature absorption spectra are reported for NpCl3 and NpBr3 in the range 3300–40 000 cm−1. Term assignments are made to a number of excited levels not previously identified, and the data are interpreted in terms of a refined free-ion model. Some of the parameters associated with this model are found to have similar values for both 3+ actinide and lanthanide chlorides. The values determined for other of the parameters are in good agreement with those calculated independently using Hartree-Fock methods. The similar crystal-field quantum number ordering of levels in the ground states of actinide trichlorides and analogous lanthanides doped into LaCl3 is noted and discussed.

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Laser drilling has become a valuable tool for the manufacture of high precision micro holes in a variety of materials. Laser drilled precision holes have applications in the automotive, aerospace, medical and sensor industry for flow control applications. The technology is competing with conventional machining micro electro-discharge machining in the field of fuel injection nozzle for combustion engines. Depending on the application, laser and optics have to be chosen which suits the requirements. In this paper, the results achieved with different lasers and drilling techniques will be compared to the hole specifications in flow control applications. The issue of geometry control of high aspect ratio laser drilled holes in metals will be investigated. The comparison of flow measurement results to microscopic hole dimension measurement show that flow characteristics strongly depend on cavitation number during flow.

The influence of thermal conduction into the substrate during excimer laser ablation of thin film ZnS on silicon has been investigated. An analytical solution of the heat diffusion equation for a two-layer system has been used to calculate temperature profiles within the film and substrate arising from laser irradiation. The experimentally observed ablation rates are found to correlate with calculated surface temperatures, thereby demonstrating that thermal conduction into the substrate influences the ablation characteristics. Thus we are able to provide a simple predictive model for the ablation rate at any fluence incident on any thin film thickness. We find that for very thin films, optical interference effects reduce the energy coupled into the films and it is necessary to consider these within the model.