Photochemical laws; photochemistry and photophysics; spectra and photochemistry of co-ordination compounds; copper, silver, and gold; magnesium, zinc, cadmium, and mercury; aluminum, gallium, indium, thallium, yttrium, lanthanides, and actinides; silicon, germanium, tin, lead, and titanium; antimony, bismuthy, vanadium, niobium, and tantalum; tellurium, chromium, molybdenum, and tungsten; manganese, technetium, and rhenium; nickel, palladium, and platinum.