Visibility of colors underwater using artificial illumination.
The visibility of various colors underwater with artificial illumination has been measured in three different bodies of water chosen to sample a continuum from clear to turbid. Subjects were Scuba divers who observed the colors at night, using a mercury or an incandescent light source. The visibility results show numerous interactions among color, fluorescence, type of light source, and type of water; from them, it is possible to select the optimum combination to be used under a wide variety of conditions.
The Transparency of Ocean Water and the Visibility Curve of the Eye
Measurements of the absorption of ocean water for monochromatic light throughout the visible spectrum are recorded and show that the sea water is about as transparent as pure water. When daylight is passed through 40 meters of water the resulting spectral intensity curve is very similar to the visibility curve of the eye both as regards shape and the position of the maximum. Early life on the earth developed in a watery environment with a vaporous atmosphere. This permits the suggestion that the visibility curve of the eye owes its general characteristics to the spectral intensity curve of Palaeozoic daylight.
Resonant Auger decay study of C1s -> pi* core-excited OCS
The present work aims at characterizing short-lived C1s((-1)) pi*((1)) core-excited states of the OCS molecule based on the analysis of the vibrational fine structure and lineshape profiles of the high-resolution resonant Auger decay spectra recorded at the excitation energies along the C1s -> pi* resonance in the binding energy region 15-19eV. Very different behavior in terms of lineshape and resonant enhancement is observed for the (A) over tilde, (B) over tilde and (C) over tilde final states. This is explained by (1) the variation in the C-O bond lengths for the states involved in the electronic relaxation and (2) different contributions in terms of Mulliken population to the molecular orbitals determining the electronic character of the corresponding states. Since the final-state geometries are known from a number of previous experiments and ab initio calculations, the geometry of the C1s((-1)) pi*((1)) intermediate states can be predicted in analogy with e.g. the N-2, CO2 and N2O molecules. (C) 2009 Elsevier B.V. All rights reserved. (Less)