Blue glow

The dynamic range of the fluorescence experiment is related to a number of factors but it can be orders of magnitude. It is possible, for example, to determine quinine in water from nanomolar to millimolar concentration by direct measurement. Quinine fluorescence is familiar to most people that have noticed the blue glow of quinine tonic water in sunlight. 

Figure 3.5 reveals that the low-pressure ignition of CO—02 is characterized by an explosion peninsula very much like that in the case of H2—02. Outside this peninsula one often observes a pale-blue glow, whose limits can be determined as well. A third limit has not been defined and, if it exists, it lies well above 1 atm. 

The purpose of this note is to call attention once more and to explain a continuous spectrum in hydrogen that has been observed by Horton and Davies and by Crew and Hulburt and others, and possessing the peculiar characteristic of occurring without the presence of either atomic or molecular lines. Horton and Davies observed that hydrogen at pressures less than 1 mm. of mercury became suffused with a blue glow when excited by electrons of less than 15 volts velocity. This glow was a continuous spectrum showing no trace of atomic or molecular lines. 

With the aid of a new liquid-air machine, generously provided by Dr. Ludwig Mond, Professor Ramsay and Dr. Travers prepared larger quantities of krypton and neon, and by repeated fractionation of krypton, a still heavier gas was separated from it, which they named xenon, the stranger (15). It was discovered on July 12, 1898. Vacuum tubes containing it show forth a beautiful blue glow. 

BLUE GLOW. A type of luminescence emitted by certain metallic oxides, when heated. A blue glow is normally seen in electron tubes containing mercury vapor, arising from the ionization of the molecules in the mercury vapor. 

The light blue glow given off by mercury streetlamps has a wavelength of 436 nm. What is its frequency in hertz ... 

Does the blue glow from this mercury lamp correspond to a longer or shorter wavelength than the yellow glow from a sodium lamp ... 

Recombination of the above species led to the release of energy in the form of a blue glow and copious amounts of ultra-violet light. The UV photons had sufficient energy to break carbon-carbon and carbon-hydrogen bonds in the polymers ... 

Cherenkov radiation is electromagnetic radiation emitted when a charged particle (such as an electron) passes through an insulator at a constant speed greater than the phase velocity of light in that medium. The characteristic "blue glow" of nuclear reactors is due to Cherenkov radiation. 

As the flow of NO2 increases, the blue glow fades to a dark end point corresponding to complete consumption of N and N02 . The main condensible product in the reaction between NO2 and active nitrogen is N2O and at the end point the yield of N2O per N atom consumed is approximately 26 There is general agreement that the reactions... 

The blue glow of excited nitric oxide persists as long as nitrogen atoms are in... 

Heating method. Once again the reactants, say CO and 02 , are pre-mixed in the RV but at a low temperature. The temperature is gradually raised when the pressure increases according to Charles Law. At a critical pressure a blue glow appears. At this point contraction occurs due to reaction. As the temperature is raised, the intensity of the glow increases and finally a flash occurs. This is accompanied by a pressure kick. The pressure limit is taken as that at which the blue glow first appears. A variation of this is also used with a flow system (see p. 24). 

A small amount (about 0.01 g) of indanthrene dark blue is placed in a wash bottle. 20 mL of CH2CI2, 60 mL of 6 mol/L NaOH and 20 mL of a 30 % H2O2 solution are added. The room is darkened and chlorine passed through the solution. After a short time the gas bubbles are surrounded by a beautiful carmine glow. A lovely lavender blue glow is obtained when luminol is used. 

If pre-cut lithium is introduced, the conversion may be slower, because the surface of the metal is coated with oxide and nitride. During cutting a red to blue glow appears on the surface of the metal, due to adsorption of ammonia vapour. 

In 1663 Boyle observed that diamonds become luminous if rubbed in the dark they become luminous, too, after exposure to light or to cathode rays. When exposed to ultraviolet light some diamonds yield a blue glow. They are more transparent to X-rays than other gems and after prolonged exposure to radium a colourless diamond becomes green. 

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