The absolute transition probabilities between the 3p⁵4s and 3p⁵4p configurations of neutral argon have been measured in a three part experiment. In the first experiment, a technique of absorption spectroscopy was used to obtain relative transition probabilities for spectral lines with a common lower level. Secondly, relative transition probabilities were obtained for spectral lines with a common upper level by measuring the relative intensities of suitable pairs of lines in an emission experiment. In the third experiment, the relative values were converted to absolute transition probabilities by obtaining the lifetime of the P₁-S2 transition at ʎ7503Å. The experimental techniques used in this experiment were developed by Robinson (1966) and van Andel (1966). / Science, Faculty of / Physics and Astronomy, Department of / Graduate

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Thesis--Utrecht. / Foreword in Dutch; summary in Dutch and English. Curriculum vitae (In Dutch). Includes bibliographical references.

Thesis--Utrecht. / Foreword in Dutch; summary in Dutch and English. Curriculum vitae (In Dutch). Includes bibliographical references.

No description available.

The beam-foil method was used to determine mean-lives of excited atomic states. Initial studies were done on states. Initial studies were done on states of the helium- and hydrogen-like ions B IV and B V, with the mean-lives determined by fitting the decay curves to sums of exponential terms. Since theoretical values of the mean-lives are very precise in these simple atomic systems, our results indicate the accuracy of the experimental method. A series of measurements was made of the low lying 2s 2p⁴ states in nitrogen-like Ne IV, Na V, Mg VI, Al VII, and Si VIII. The experimental results were compared to theoretical calculations of Fawcett and Sinanoglu, and showed excellent agreement with Sinanolu's nonclosed-shell many electron theory. The lifetimes of the 4p ²P₁/₂ and 4p ²P₃/₂ states in copper-like Br VII were determined by measuring decay curves for both the primary and cascade decays and then analyzing the curves jointly. Our resulting mean-life values are considerbly shorter than those of previous experiments which analyzed only the primary decay curve. Comparison with theoretical calculations showed excellent agreement with those which include core polarization effects.

A scheme, analogous to the linear combination of atomic orbitals (LCAO), is used to calculate rates of reactions for the fusion of nuclei con¯ned in molecules. As an example, the possibility of nuclear fusion in rotationally excited H2O molecules of angular momentum 1¡ is estimated for the p + p + 16O ! 18Ne¤(4:522; 1¡) nuclear transition. Due to a practically exact agreement of the energy of the Ne resonance and of the p + p + 16O threshold, the possibility of an enhanced transition probability is investigated. / Physics / M.Sc.

A scheme, analogous to the linear combination of atomic orbitals (LCAO), is used to calculate rates of reactions for the fusion of nuclei con¯ned in molecules. As an example, the possibility of nuclear fusion in rotationally excited H2O molecules of angular momentum 1¡ is estimated for the p + p + 16O ! 18Ne¤(4:522; 1¡) nuclear transition. Due to a practically exact agreement of the energy of the Ne resonance and of the p + p + 16O threshold, the possibility of an enhanced transition probability is investigated. / Physics / M.Sc.