The Nature of Animal LightHarvey, E. Newton (Edmund Newton)
Science
The Nature of Animal Light
Harvey, E. Newton (Edmund Newton)
Phosphorescence
I believe the explanation of these phenomena lies rather in another
direction and that the effect of the temperature and concentration of
reacting substances affects not only the reaction velocity but also the
reaction products. While intensity of luminescence undoubtedly increases
with increasing reaction velocity, the luminescence itself probably
accompanies only one stage in the formation of a series of oxidation
products. This stage is favored at a definite temperature and mass of
reacting substances. Thus, in the oxidation of phosphorus several
intermediate oxides are said to be formed. The oxidation takes place in
steps and probably the luminescence is connected with only one of the
steps in a chain of reactions. It is probable that a certain oxygen
pressure and temperature favors that particular step at the expense of
the others and so this oxygen concentration and temperature correspond
to the optimum for luminescence.
The supposition that certain definite oxidation products of pyrogallol
must be formed in order to produce light is borne out by the fact that
pyrogallol must be oxidized in a particular way to obtain luminescence.
The blackening of pyrogallol with absorption of oxygen in presence of
alkali is a very well-known reaction, but luminescence does not
accompany this type of oxidation. I have tried mixing all concentrations
of pyrogallol and all concentrations of alkali in an endeavor to obtain
some light, but always with negative results. Likewise my attempts to
obtain light during the electrolysis of salt solutions containing
pyrogallol by means of the nascent oxygen at various kinds of anodes
have met with negative results. A similar case is presented by luciferin
which oxidizes spontaneously (most rapidly in presence of alkali)
without light production and only produces light when oxidized in
presence of luciferase.
To sum up the results of the dynamics of chemiluminescence we may say
that certain oxyluminescences occur only if the substance is oxidized in
a particular way under definite conditions of temperature and
concentration and that this is probably due to a favoring of one step
(with which the luminescence is associated) in a chain of oxidations.
Providing temperature and concentration are such as to favor the step
responsible for luminescence, then higher temperature and greater
concentration result in increased intensity of luminescence.
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