Symmetries of SU(2) invariant Yang-Mills theories

It is shown that both the field equations and the self-duality equations of SU(2) invariant Yang-Mills theories do not allow any other Lie symmetries than those they have by construction, i.e., the 15 generators of the conformal group and the 3 generators of the gauge group. This is true in Euclidean as well in Minkowskian space-time.     

Über die Ablenkung des Lichtes im Schwarzschild-Raum

On the Deflection of Light in Schwarzschild-Space A trigonometric approximation formula for the paths of light in Schwarzschild-Space is derived. A formula for the deflection angle at the Earth is given. Then we describe and calculate an experiment, where angles change the value by 1/2 · 1.75′ without a solar eclipse being necessary.     

Steric Interactions in Organic Chemistry: Spatial Requirements of Substituents

From the very extensive factual material available on steric interactions in organic chemistry, the present paper reviews the investigations that provide information about the “size” (“spatial requirement”) of the substituents. After an introductory section on the results obtained with the aid of spectroscopic data and by analysis of chemical reactions, attention is turned to conformational processes, including hindered rotation in ethanes, in the biphenyl system, in butadienes, multiply substituted arenes, molecular propellers, and triptycenes. The main emphasis is placed on the explanation of sterically hindered ring inversions in bridged arenes, a class of compounds particularly suitable for the study of steric interactions. The results obtained by variation of the parameters in this system are also discussed with respect to the spatial requirements of organic substituents.