Diabacy

Surname

Diabacy

${\ displaystyle \ Theta}$

Size and unit system	unit	dimension
SI

The Diabatie (also spectral Diabatie ) is in the optics , a dimensionless quantity , which with the aid of attenuation of light when passing through a substance is described. ${\ displaystyle \ Theta}$

The diabacy takes into account the exponential dependence of the extinction on the thickness of the irradiated material by forming a further logarithm . As a result, the difference between the diabatia of a substance at two different wavelengths of light does not depend on the layer thickness. Thus the spectral distribution of the diabatia is largely independent of the parameters of the measurement, but is characteristic of each substance . ${\ displaystyle \ lambda}$ ${\ displaystyle \ Theta (\ lambda)}$

definition

The diabacy is the decadic logarithm of ten times the reciprocal of the absorbance : ${\ displaystyle \ Theta}$ ${\ displaystyle E}$

{\ displaystyle {\ begin {aligned} \ Theta (\ lambda) & = \ lg {\ frac {10} {E (\ lambda)}} \\ & = 1+ \ lg {\ frac {1} {E ( \ lambda)}} \\ & = 1- \ lg {E (\ lambda)} \\ & = 1- \ lg \ left (\ lg {\ frac {1} {\ tau (\ lambda)}} \ right ) \ end {aligned}}}

Here is the degree of transmission . ${\ displaystyle \ tau}$

properties

The characteristic curve of the spectral diabacy of a substance over frequency is independent of its layer thickness. The layer thickness differences are shown in the form of a shift in the direction of the ordinate axis . For a graphical representation, the layer thickness is expediently chosen in such a way that positive values always result for the spectral diabacy.

With very high values of the extinction (from about 0.6 to 1.0) or very low values of the pure spectral transmittance (10 ⁻⁵ ), differences between two substances are shown more clearly.

literature

Transmission of optical radiation through media. Optically clear fabrics Sizes, symbols and units. DIN 1349 sheet 1, June 1972.
Peter Kurzweil: The Vieweg formula lexicon: basic knowledge for engineers, natural scientists and medical professionals . Vieweg + Teubner, 2002, ISBN 978-3-528-03950-9 , pp. 258 .
Heinz Haferkorn: Optics: Physical-technical basics and applications . Wiley-VCH, 2003, ISBN 978-3-527-40372-1 , pp. 67 .